EN： The Past Perfect tense ('had' + past participle) is used to show that an action was completed before another action in the past. In this sentence, 'had closed' happened before 'arrived'.
中文： 过去完成时（had + 过去分词）用于表示在过去某个动作或时间点之前就已经完成的动作。在本句中，「博物馆关门（had closed）」发生在「我们到达（arrived）」之前。
By the time the movie started, we had already bought our popcorn.
在电影开始之前，我们就已经买好爆米花了。
EN： The phrase 'by the time' is a subordinating conjunction used to introduce a time clause, meaning 'no later than the moment that'. It is commonly paired with the past perfect in the main clause to show sequence.
中文： 短语「by the time」是一个从属连词，用来引导时间状语从句，意思是「最迟在…之时」或「到了…的时候」。它通常与主句中的过去完成时搭配使用，以显示事情发生的先后顺序。
By the time she called me, I had left the office.
在她打电话给我时，我已经离开办公室了。
EN： The Past Perfect tense (had + past participle) is used to describe an action that was completed before another action or a specific time in the past. In this question form, 'Had' is placed before the subject.
中文： 过去完成时（had + 过去分词）用于描述在过去某个动作或特定时间点之前就已经完成的动作。在疑问句中，会将助动词「Had」置于主语之前。
Had you finished the report before the meeting started?
在会议开始之前，你已经完成报告了吗？
EN： The word 'before' is used here as an adverb meaning 'at an earlier time' or 'previously', positioned at the end of the sentence to emphasize that the action should have occurred prior to the main past event (arriving at the museum).
中文： 「before」在此处用作副词，意思是「以前」或「事先」，放在句尾以强调该动作应该在过去的主要事件（到达博物馆）之前发生。
EN： In English-speaking countries, 'the hours' is a common shorthand for 'opening hours' or 'business hours' of museums, shops, or restaurants. Checking these in advance is a highly recommended travel habit due to seasonal variations.
中文： 在英語系國家，「the hours」是博物館、商店或餐廳「營業時間（opening hours / business hours）」的常見簡稱。由於當地營業時間常隨季節或節假日變動，行前先確認時間是十分普遍且被建議的旅遊習慣。
EN： The Past Perfect Tense ('had' + past participle) is used to describe an action or state that occurred before another action or a specific time in the past. In this sentence, 'had never been' emphasizes the state of disappointment experienced prior to the end of the trip.
中文： 过去完成时（had + 过去分词）用于描述在过去某个动作或特定时间点之前就已经发生或完成的动作或状态。在本句中，「had never been」强调在本次旅行结束前的这段时间里，说话者从未有过如此失望的感受。
By the time we arrived, the museum had closed.
在我们到达之前，博物馆就已经关门了。
EN： The structure 'so + adjective + on a trip' is used to express a high degree of an emotion or state experienced during a journey. 'So' acts as an intensifying adverb modifying the adjective 'disappointed'.
中文： 「so + 形容词 + on a trip」的结构用于表达在旅途中所感受到的强烈情绪或状态。「so」作为程度副词，用来修饰形容词「disappointed」（失望的）。
I had never been so excited on a trip.
我从未在旅行中感到如此兴奋。
EN： The Past Perfect tense ('had' + past participle) is used to show that an action was completed before another action in the past. In this sentence, 'the tour had left' happened before 'we reached the gate'.
中文： 过去完成时（had + 过去分词）用于表示在过去某个动作或时间点之前就已经完成的动作。在本句中，「旅行团已经离开（had left）」发生在「我们到达登机口（reached）」之前。
By the time the movie started, we had already bought our popcorn.
在电影开始之前，我们就已经买好爆米花了。
EN： The phrase 'by the time' is a subordinating conjunction used to introduce a time clause, meaning 'no later than the moment that'. It is commonly paired with the past perfect in the main clause to show sequence.
中文： 短语「by the time」是一个从属连词，用来引导时间状语从句，意思是「最迟在...之时」或「到了...的时候」。它通常与主句中的过去完成时搭配使用，以显示事情发生的先后顺序。
By the time she arrived at the station, the train had left.
当她到达车站时，火车已经开走了。
EN： In travel contexts, 'the gate' usually refers to an airport departure gate, but in the context of tours or attractions, it can also refer to the main entrance gate of a venue or park. Missing a tour departure due to minor delays is a common travel anxiety shared globally.
中文： 在旅遊情境中，「the gate」通常指機場的登機門，但在旅行團或景點的語境下，它也可以指景區或公園的大門。因為些微的延誤而錯過旅行團的出發時間，是全球旅客共同面臨的常見焦慮。
EN： The Past Perfect tense (had + past participle) is used to describe an action that was completed before another action or a specific time in the past.
中文： 过去完成时（had + 过去分词）用于描述在过去某个动作或特定时间点之前就已经完成的动作。
She had already left when I arrived at the station.
当我到达车站时，她已经离开了。
EN： The prepositional phrase 'by mistake' is used as an adverbial modifier meaning accidentally or without intending to.
中文： 介词短语“by mistake”用作状语修饰语，意思是“不小心地”或“无意中地”。
I took your umbrella by mistake.
我不小心拿错了你的雨伞。
EN： The Past Perfect tense (had + past participle) is used to describe an action that happened before another action or state in the past. In this sentence, 'had walked' happened before the state of being 'tired'.
中文： 过去完成时（had + 过去分词）用于描述在过去某个动作或状态之前就已经发生的动作。在本句中，「走路（had walked）」发生在「疲累（tired）」这个过去状态之前。
She was hungry because she had not eaten lunch.
她那时很饿，因为她没有吃午餐。
EN： The subordinating conjunction 'because' is used to introduce a clause that gives the reason for the action or state in the main clause.
中文： 从属连词「because（因为）」用于引导一个表示原因的从句，用来解释主句中动作或状态发生的原因。
We stayed home because it was raining.
我们待在家里，因为那时正在下雨。
EN： The Past Perfect tense ('had' + past participle) is used to show that an action was completed before another action or a specific time in the past.
中文： 过去完成时（had + 过去分词）用于表示在过去某个动作或特定时间点之前，就已经完成的动作。
She had finished her homework before her friends arrived.
在她的朋友到达之前，她就已经写完作业了。
EN： The conjunction 'before' is used to connect two clauses, indicating that the action in the main clause happened prior to the action in the adverbial clause.
中文： 连接词“before”（在……之前）用于连接两个从句，表示主句的动作发生在状语从句的动作之前。
We washed our hands before we ate dinner.
我们在吃晚饭前洗了手。
EN： The Past Perfect tense ('had' + past participle) is used to show that an action was completed before another action in the past. In this sentence, 'had eaten' happened first, and 'found' happened second.
中文： 过去完成时（had + 过去分词）用于表示在过去某个动作或时间点之前就已经完成的动作。在此句子中，“吃完饭（had eaten）”发生在前，“找到公园（found）”发生在后。
After she had finished her homework, she watched a movie.
她写完作业后，看了一部电影。
EN： The subordinating conjunction 'after' introduces an adverbial clause of time. When the 'after' clause comes at the beginning of the sentence, a comma is used to separate it from the main clause.
中文： 从属连词“after（在……之后）”引导时间状语从句。当“after”引导的从句置于句首时，主句与从句之间必须使用逗号隔开。
After we had arrived at the hotel, we unpacked our bags.
我们到达酒店后，整理了行李。
EN： The Past Perfect tense ('had' + past participle) is used to show that an action was completed before another action in the past. In this sentence, leaving the map ('had left') happened before realizing it ('realized').
中文： 过去完成时（had + 过去分词）用于表示在过去某个动作或时间点之前就已经完成的动作。在本句中，「遗忘地图」（had left）发生在「意识到」（realized）之前。
She realized she had forgotten her passport at the hotel.
她意识到她把护照忘在酒店了。
EN： The conjunction 'that' is often omitted in informal English when introducing a noun clause acting as the direct object of verbs like 'realize', 'think', or 'know'.
中文： 在非正式英语中，当引导名词性从句作为「realize（意识到）」、「think（认为）」或「know（知道）」等动词的直接宾语时，连词「that」通常会被省略。
I think we took the wrong turn.
我想我们转错弯了。
EN： The Past Perfect tense ('had' + past participle) is used to describe an action that was completed before another action in the past. In this sentence, 'had sold' happened before the past action 'came'.
中文： 过去完成时（had + 过去分词）用于描述在过去某个动作或时间点之前就已经完成的动作。在此句子中，「had sold」（卖完）发生在过去动作「came」（到来）之前。
The train had already left when we arrived at the station.
当我们到达车站时，火车已经开走了。
EN： The conjunction 'before' is used to connect two clauses, indicating that the action in the main clause (Past Perfect) occurred prior to the action in the subordinate clause (Simple Past).
中文： 连词「before」（在...之前）用于连接两个从句，表示主句的动作（过去完成时）发生在从句的动作（一般过去时）之前。
She had finished her homework before she went to bed.
她在上床睡觉之前就已经完成了作业。
EN： The Past Perfect tense ('had' + past participle) is used to describe an action that was completed before a specific point in the past. In this sentence, 'had never traveled' indicates that prior to the past trip being discussed, the speaker had no experience of traveling so far.
中文： 过去完成时（had + 过去分词）用于描述在过去某个特定时间点之前已经完成的动作或经历。在本句中，「had never traveled」表示在所讨论的该次过去旅行之前，说话者从未有过旅行到那么远的经历。
She had never seen the ocean before she visited California.
在她造访加州之前，她从未见过海洋。
EN： The adverb 'so' is used as an intensifier before adjectives or adverbs (like 'far') to mean 'to such a great degree' or 'extremely'.
中文： 副词「so」在形容词或副词（如「far」）前用作强调词，表示程度极深，意为「如此地」或「非常地」。
I didn't know the hotel was so close to the station.
我不知道那家酒店离车站这么近。
EN： In English-speaking cultures, sharing personal travel milestones (like traveling far from home for the first time) is a common way to build rapport and share life experiences during casual conversations.
中文： 在英語系國家的文化中，分享個人的旅行里程碑（例如第一次遠行）是日常社交對話中建立關係、分享生活經驗的常見話題。
EN： The Past Perfect tense ('had' + past participle) is used to describe an action that was completed before another action or a specific point in the past. In this sentence, 'had saved' indicates that the backup plan was prepared before the main past event or situation occurred.
中文： 过去完成时（had + 过去分词）用于描述在过去某个动作或特定时间点之前就已经完成的动作。在本句中，「had saved」表示在过去的某个主要事件或状况发生之前，我们就已经准备好了备用方案。
By the time the storm started, we had found a safe shelter.
在暴风雨开始之前，我们就已经找到了一个安全的避难所。
EN： The adverb 'Luckily' is used as a sentence modifier (or comment adverb) to express the speaker's attitude toward the entire situation. It is typically placed at the beginning of the sentence and followed by a comma.
中文： 副词「Luckily」（幸好／幸运地）在此用作句子修饰语（或称评注性副词），用来表达说话者对整个状况的态度。它通常置于句首，后面加上逗号。
Luckily, the rain stopped before our outdoor wedding began.
幸好，在我们的户外婚礼开始之前，雨就停了。
EN： In travel and project management contexts, having a 'backup plan' (often referred to as 'Plan B') is highly valued in Western culture. It reflects a proactive attitude toward uncertainty and unexpected disruptions, which are common themes in travel narratives.
中文： 在旅遊和專案管理的語境中，準備「backup plan」（備用方案，通常也稱為 Plan B）在西方文化中非常受到重視。這反映了對不確定性和突發狀況（這在旅遊敘事中很常見）採取未雨綢繆、積極應對的態度。
EN： The simple past tense is used to describe completed actions in the past. In this sentence, 'took' is the irregular past tense form of the verb 'take'. It is often accompanied by past time expressions like 'last summer'.
中文： 一般过去时用于描述过去已完成的动作。在此句子中，“took”是动词“take”的不规则过去式变化。通常与过去的时间状语（如“last summer”去年夏天）连用。
Last year, we took a train to Paris.
去年，我们坐火车去了巴黎。
EN： The collocation 'take a trip' means to travel or go on a journey. It is commonly followed by the preposition 'to' to indicate the destination.
中文： 动词短语“take a trip”意为“去旅行”。后面通常接介词“to”来表示目的地。
They want to take a trip to Japan next winter.
他们明年冬天想去日本旅行。
EN： The Past Perfect tense ('had' + past participle) is used to describe an action that was completed before another action in the past. In this sentence, 'had planned' happened before the past action 'left'.
中文： 过去完成时（had + 过去分词）用于描述在过去某个动作或时间点之前就已经完成的动作。在本句中，「计划好」（had planned）发生在另一个过去动作「离开」（left）之前。
She had already finished her homework before her friends arrived.
在她的朋友到达之前，她就已经写完作业了。
EN： The conjunction 'before' is used to connect two clauses, indicating that the action in the main clause (Past Perfect) occurred prior to the action in the subordinate clause (Simple Past).
中文： 连词「before」（在……之前）用于连接两个从句，表示主句的动作（过去完成时）发生在从句的动作（一般过去时）之前。
They had locked the door before they went to bed.
他们在上床睡觉之前就把门锁好了。
EN： The Past Perfect tense ('had' + past participle) is used to show that an action was completed before another action or a specific time in the past.
中文： 过去完成时（had + 过去分词）用于表示某个动作在过去的另一个动作或特定时间点之前就已经完成。
By the time the movie started, we had already bought our popcorn.
在电影开始之前，我们就已经买好爆米花了。
EN： The time clause 'by the time' means 'not later than the moment that' and is commonly used with the Past Perfect in the main clause to show sequence of events.
中文： 时间状语从句接「by the time」（到了…的时候/在…之前），主句通常搭配过去完成时，用来强调两个过去事件的先后顺序。
By the time she called me, I had already left the office.
在她打电话给我时，我已经离开办公室了。
EN： The Past Perfect Tense ('had' + past participle) is used to describe an action that occurred before another action in the past. In this sentence, taking the wrong train ('had taken') happened before they realized it ('realized').
中文： 过去完成时（had + 过去分词）用于描述在过去某个动作或时间点之前就已经发生的动作。在本句中，「搭错火车」（had taken）发生在「意识到」（realized）之前。
She realized that she had left her keys at the office.
她意识到她把钥匙留在办公室了。
EN： The noun clause introduced by 'that' acts as the direct object of the verb 'realized'. It contains the complete thought or fact that was realized. In informal English, 'that' can often be omitted.
中文： 由「that」引导的名词性从句作为动词「realized」的直接宾语，包含被意识到的完整想法或事实。在非正式英语中，「that」通常可以省略。
I believe that we made the right decision.
我相信我们做出了正确的决定。
EN： The past perfect tense ('had' + past participle) is used here with 'never' to describe an experience that had not occurred up to a specific point in the past (the time of the trip).
中文： 过去完成时（had + 过去分词）在此与 'never'（从未）连用，用来描述在过去某个特定时间点（旅行当时）之前，从未发生过的经历。
Before that day, I had never seen such a beautiful sunset.
在那天之前，我从未见过如此美丽的日落。
EN： The linking verb 'feel' is followed by the past participle 'lost' acting as an adjective to describe the subject's emotional or physical state.
中文： 系动词 'feel'（感觉）后面接过去分词 'lost'（迷失的）作为形容词，用来描述主语的情感或身体状态。
She felt exhausted after the long flight.
在长途飞行后，她感到筋疲力尽。
EN： The Past Perfect tense ('had' + past participle) is used to describe an action that was completed before another action or point of time in the past.
中文： 过去完成时（had + 过去分词）用于描述在过去某个时间点或另一个过去动作之前，就已经完成的动作。
By the time we arrived at the station, the train had already left.
当我们到达车站时，火车已经开走了。
EN： The adverb 'luckily' is used as a sentence modifier to express the speaker's attitude toward the situation, meaning 'it is fortunate that...'. It is usually placed at the beginning of the sentence.
中文： 副词“luckily”（幸好、幸运地）用作全句修饰语，表示说话者对情况的评价，意思是“很幸运的是……”，通常置于句首并用逗号隔开。
EN： The Past Perfect tense ('had' + past participle) is used to show that an action was completed before another action in the past. In this sentence, 'had rested' happened first, and 'found' happened second.
中文： 过去完成时（had + 过去分词）用于表示在过去某个动作或时间点之前就已经完成的动作。在本句中，「休息」（had rested）发生在先，「找到」（found）发生在后。
After she had finished her homework, she watched TV.
在她写完作业之后，她看了电视。
EN： Adverbial clauses of time introduced by 'after' describe when the main action took place. When the adverbial clause comes first, it is separated from the main clause by a comma.
中文： 由「after」（在……之后）引导的时间状语从句，用来描述主句动作发生的时间。当状语从句放在句首时，与主句之间必须用逗号隔开。
After we had packed our bags, we checked out of the hotel.
在我们收拾好行李之后，我们办理了退房手续。
EN： The Past Perfect Tense (had + past participle) is used to describe an action that was completed before another action or a specific point in the past. In this sentence, 'had not given up' happened before the state of being happy ('were happy').
中文： 过去完成时（had + 过去分词）用于描述在过去某个动作或特定时间点之前就已经完成的动作。在本句中，「没有放弃」（had not given up）发生在「感到高兴」（were happy）之前。
They were relieved because they had found their lost keys.
他们松了一口气，因为他们找到了遗失的钥匙。
EN： The phrasal verb 'give up' means to stop making an effort or to resign to defeat. In the past perfect tense, 'give' becomes 'given'. When negated, 'not' is placed between 'had' and the past participle 'given'.
中文： 短语动词「give up」意为停止努力或放弃。在过去完成时中，「give」变为过去分词「given」。否定时，将「not」放在「had」与过去分词「given」之间。
She had not given up on her dream despite the difficulties.
尽管困难重重，她也没有放弃她的梦想。
EN： The verb 'teach' can be used in the pattern 'teach + object + to-infinitive' (teach someone to do something) to show that someone helps another person learn a skill or behavior.
中文： 动词「teach」（教导）常用于「teach + 宾语 + 不定式」（教导某人做某事）的句型，用来表示帮助某人学习某种技能或行为态度。
My mother taught me to cook when I was young.
我母亲在我年轻时教我做饭。
EN： The verb 'stay' can function as a linking verb followed by an adjective (e.g., 'stay calm', 'stay healthy') to mean remaining in a particular state or condition.
中文： 动词「stay」可作为系动词，后接形容词（例如「stay calm」保持冷静、「stay healthy」保持健康），表示维持在某特定的状态或情况中。
Please stay quiet during the performance.
演出期间请保持安静。
EN： Wh-questions with the verb 'to be' in the past simple tense. In this structure, the question word (Why) is followed by the past tense form of 'be' (were), then the subject (you), and finally the adjective/complement (late).
中文： 使用过去时 be 动词的 Wh- 问句。在此结构中，疑问词 (Why) 后面接 be 动词的过去式 (were)，接着是主语 (you)，最后是形容词/补语 (late)。
Why were you angry at the meeting yesterday?
你昨天开会时为什么生气？
EN： The prepositional phrase 'late to [a place]'. While 'late for' is commonly used for events (e.g., late for school, late for work), 'late to' is often used when emphasizing the destination or arrival at a specific physical location like an airport or station.
中文： 介词短语“late to [地点]”。虽然“late for”通常用于活动（例如：上学迟到、上班迟到），但“late to”常用于强调到达特定实体地点（如机场或车站）的迟到情况。
She was late to the train station and missed her ride.
她去火车站迟到了，结果错过了火车。
EN： In Western travel culture, arriving late to an airport is a common source of high stress due to strict security checks and boarding cut-off times. Asking 'Why were you late...' in a supportive tone is a common way to show concern after a stressful travel event.
中文： 在西方旅遊文化中，由於嚴格的安全檢查和登機截止時間，去機場遲到通常是極大壓力的來源。以關切的語氣詢問「你為什麼遲到……」，是經歷壓力緊繃的旅行事件後，表達關心與好奇的常見方式。
EN： The Past Perfect tense ('had' + past participle) is used to show that an action was completed before another action in the past. In this sentence, 'had left' happened before 'came down'.
中文： 过去完成时（had + 过去分词）用于表示在过去某个动作或时间点之前就已经完成的动作。在此句子中，「出租车开走 (had left)」发生在「我下楼 (came down)」之前。
The train had already departed before we reached the station.
在我们到达车站之前，火车就已经出发了。
EN： The subordinating conjunction 'before' introduces an adverbial clause of time, indicating the sequence of events. The clause following 'before' typically uses the Simple Past tense when paired with the Past Perfect in the main clause.
中文： 从属连词「before（在……之前）」引导时间状语从句，用来表示事件的先后顺序。当主句使用过去完成时时，由 before 引导的从句通常使用一般过去时。
She had finished her homework before she went to bed.
她在上床睡觉之前就已经写完了作业。
EN： The Past Perfect Tense ('had' + past participle) is used to describe an action that was completed before another action or a specific time in the past.
中文： 过去完成时（had + 过去分词）用于描述在过去某个动作或特定时间点之前，就已经完成的动作。
She had finished her homework before her mother came home.
在妈妈回到家之前，她已经做完作业了。
EN： The conjunction 'before' is used to connect two clauses, indicating that the action in the main clause (Past Perfect) happened prior to the action in the adverbial clause (Simple Past).
中文： 连词「before」（在...之前）用于连接两个从句，表示主句的动作（过去完成时）发生在状语从句的动作（一般过去时）之前。
They had left the office before the rain started.
在下雨之前，他们就已经离开办公室了。
EN： The Past Perfect tense (had + past participle) is used here in its question form ('Had you + past participle') to ask about an experience that occurred before a specific point in the past. The adverb 'ever' is commonly used in questions to mean 'at any time before now'.
中文： 过去完成时（had + 过去分词）在此处以疑问句形式（Had you + 过去分词）呈现，用来询问在过去某个特定时间点之前是否曾有过某个经历。副词“ever”常用于疑问句中，表示“在（过去）那之前的任何时候”。
Had you ever seen a penguin before you went to Antarctica?
在你去南极洲之前，你见过企鹅吗？
EN： The Past Perfect tense ('had' + past participle) is used to describe an action that was completed before a specific point in the past. In this sentence, 'had never been' indicates that the experience of visiting that place did not occur at any point prior to 'last week'.
中文： 过去完成时（had + 过去分词）用于描述在过去某个特定时间点之前就已经完成的动作或状态。在本句中，「had never been」表示在「上周」之前的任何时间点，都未曾有过造访该地的经历。
I had never seen a glacier until I visited Alaska.
在我去阿拉斯加之前，我从未见过冰川。
EN： The preposition 'until' is used to show that an activity or situation continues up to a particular time. When paired with a negative past perfect ('had never... until'), it emphasizes that the situation changed only at that specific past moment.
中文： 介词「until」（直到……）用于表示某个活动或状态持续到特定时间点。当与否定过去完成时（had never... until）连用时，它强调了该状态直到过去的那个特定时刻才发生改变（即在上周终于去过了）。
She had not heard the news until yesterday.
直到昨天她才听到这个消息。
EN： The Past Perfect tense ('had' + past participle) is used to show that an action was completed before another action in the past. In this sentence, 'the line had grown' happened before 'we checked in'.
中文： 过去完成时（had + 过去分词）用于表示在过去某个动作或时间点之前就已经完成的动作。在本句中，“排队的人群变长（had grown）”发生在“我们办理入住（checked in）”之前。
By the time the movie started, we had already bought our popcorn.
在电影开始之前，我们就已经买好爆米花了。
EN： 'By the time' is a subordinating conjunction used to introduce a time clause, meaning 'no later than the moment that'. It is typically followed by a simple past verb when referring to past events.
中文： “By the time”是一个从属连词，用来引导时间状语从句，意思是“不迟于某个时刻”或“到了……的时候”。在描述过去事件时，其后通常接一般过去时动词。
By the time he arrived at the station, the train had left.
当他到达车站时，火车已经开走了。
EN： The Past Perfect tense ('had' + past participle) is used to describe an action that was completed before another action or point in time in the past.
中文： 过去完成时（had + 过去分词）用于描述在过去某个动作或时间点之前，就已经完成的动作。在本句中，「提前规划」（had planned）发生在「感到平静」（felt）之前。
They had already left when we arrived at the station.
当我们到达车站时，他们已经离开了。
EN： The subordinating conjunction 'because' introduces a dependent clause of reason, explaining why the action in the main clause ('We felt calm') occurred.
中文： 从属连词「because」（因为）用来引导表示原因的从句，解释主句动作（「我们感到平静」）发生的原因。
She stayed home because she was not feeling well.
她待在家里，因为她身体不舒服。
EN： The Past Perfect tense ('had' + past participle) is used to show that an action was completed before another action in the past. In this sentence, 'had booked' happened before the past action 'sold out'.
中文： 过去完成时（had + 过去分词）用于表示在过去某个动作或时间点之前就已经完成的动作。在本句中，「订位 (had booked)」发生在另一个过去动作「售罄 (sold out)」之前。
The train had already left when we arrived at the station.
当我们到达车站时，火车已经开走了。
EN： The phrasal verb 'sell out' means to sell all of the available tickets, seats, or goods. In the past tense, it becomes 'sold out'.
中文： 短语动词「sell out」意为售罄、卖光（所有的票、座位或商品）。其过去式为「sold out」。
The concert tickets sold out in just five minutes.
音乐会的门票在短短五分钟内就售罄了。
EN： The Past Perfect tense ('had' + past participle) is used to show that an action was completed before another action in the past. In this sentence, 'had landed' happened first, before the past action 'took'.
中文： 过去完成时（had + 过去分词）用于表示在过去某个动作或时间点之前已经完成的动作。在本句中，「had landed（降落）」发生在过去的另一个动作「took（休息）」之前。
After we had finished the project, we celebrated.
在我们完成项目之后，我们庆祝了一下。
EN： The phrase 'take a rest' means to stop doing an activity in order to relax or recover strength. The adjective 'quick' is used to modify 'rest' to indicate a short duration.
中文： 短语「take a rest」意思是停止活动以进行放松或恢复体力。形容词「quick（快速的）」用来修饰「rest」，表示时间很短暂的休息。
Let's take a quick rest before we climb the hill.
在我们爬山之前，先稍作休息吧。
EN： The use of 'what' as a nominal relative pronoun (also called a fused relative pronoun). It functions as 'the thing(s) that' and introduces a noun clause that acts as the direct object of the verb 'forget'.
中文： 使用「what」作为关系代词（又称融合关系代词）。它的功能相当于「the thing(s) that」（所……的事物），引导一个名词性从句，在句中作为动词「forget」的直接宾语。
I don't understand what you mean.
我不懂你指的是什么意思。
EN： The past perfect tense ('had seen') is used here to emphasize that the action of seeing occurred and was completed in the past, prior to the future-oriented perspective of 'forgetting' from that past standpoint, or to reference a specific past experience during a trip.
中文： 此处使用过去完成时（had + 过去分词「seen」），用以强调「看见」这个动作发生在过去，且在过去某个时间点（如旅程结束）之前就已经完成，与后续的记忆形成时间先后对比。
She cherished what she had learned during the summer camp.
她珍惜她在夏令营中所学到的一切。
重要单词附有 IPA 发音、定义、例句和互动式测验。
在本文中： 感到失望的，沮丧的
在本文中： 意识到，明白，领悟
在本文中： 幸好，幸运地
在本文中： 不知怎么地，以某种方式
在本文中： 陌生的，奇怪的
在本文中： 冷静的，镇静的
在本文中： 闹钟
在本文中： 着陆，降落
片语包含类型标示、双语定义、用法说明和例句。
An alternative plan to be used if the original plan fails.
备用方案，备选计划
To stop believing that something good will happen or that you can succeed.
放弃希望
To make plans for something before it happens.
提前计划，预先规划
To sell all of the available items, tickets, or goods.
售罄，卖光