EN： The Past Continuous tense (was/were + verb-ing) is used to describe an action that was in progress at a specific moment in the past. In this sentence, 'were you doing' asks about an ongoing activity.
中文： 过去进行时（was/were + 动词原形 + -ing）用于描述在过去某个特定时间点正在进行的动作。在本句中，“were you doing”询问的是当时正在持续进行的活动。
What were you watching when I called?
我打电话给你的时候，你正在看什么？
EN： The conjunction 'when' introduces a short, sudden action in the Simple Past tense ('the bell rang') that interrupts a longer, ongoing action in the Past Continuous tense.
中文： 连词“when”（当……时）引导一个使用过去时的短暂、突然发生的动作（“the bell rang”），这个动作打断了另一个正在进行的、时间较长的过去进行时动作。
I was cooking dinner when the phone rang.
电话响起时，我正在做晚餐。
EN： The Past Continuous tense (was/were + V-ing) is used to describe an action that was in progress at a specific moment in the past. It is often interrupted by a shorter action in the Simple Past tense.
中文： 过去进行时（was/were + 现在分词）用于描述在过去某个特定时间点正在进行的动作。这个动作通常会被另一个发生在过去简单时的短暂动作所中断。
I was cooking dinner when the phone rang.
当电话响起时，我正在做晚饭。
EN： The phrasal verb 'go off' means to make a sudden loud noise, such as an alarm ringing or a bomb exploding.
中文： 短语动词「go off」在这里的意思是（警报器、闹钟等）突然响起，或（炸弹）爆炸。
My alarm goes off at 6:00 AM every morning.
我的闹钟每天早上六点钟响起。
EN： In Western schools and workplaces, fire drills and alarm testing are very common safety procedures. The phrase 'the alarm went off' in a school context usually refers to a fire alarm or a scheduled drill, which requires everyone to evacuate calmly.
中文： 在西方學校和職場中，消防演習和警報測試是非常常見的安全程序。在學校情境中，'the alarm went off'（警報器響起）通常是指火警警報或例行演習，這時每個人都需要冷靜地進行疏散。
EN： The Past Continuous tense ('were eating') is used to describe an ongoing background action in the past, while the Past Simple tense ('flew') describes a shorter, completed action that interrupted it.
中文： 过去进行时（were eating）用于描述过去正在进行的背景动作，而一般过去时（flew）则用来描述打断该背景动作的较短、已完成的动作。
While I was studying, the phone rang.
当我正在读书时，电话响了。
EN： The subordinating conjunction 'while' is used to introduce a longer background action. When the 'while' clause comes at the beginning of the sentence, a comma is required to separate it from the main clause.
中文： 从属连词“while”（当……时）用于引导较长的背景动作。当 while 引导的从句放在句首时，必须用逗号与主句隔开。
While we were walking, it started to rain.
我们正在走路时，开始下雨了。
EN： Past Continuous Tense (was/were + -ing) describes an action that was in progress at a specific moment in the past. It sets the scene for what was happening when something else occurred.
中文： 过去进行时（was/were + -ing）描述过去某个特定时刻正在进行的动作。它为另一个事件发生时的背景情况设定场景。
I was studying when my friend called me.
当我的朋友打电话给我时，我正在读书。
EN： The conjunction 'when' introduces a specific moment in time (Simple Past) that interrupts or occurs during the ongoing action (Past Continuous). The Past Continuous clause typically comes first, followed by the 'when' clause with Simple Past.
中文： 连词 'when' 引入一个特定的时间点（过去简单时），打断或发生在进行中的动作（过去进行时）期间。过去进行时从句通常放在前面，然后是带有过去简单时的 'when' 从句。
She was cooking when the power went out.
当停电时，她正在做饭。
EN： In English-speaking educational contexts, describing what students were doing when an interruption occurred is a common way to narrate classroom events. This sentence structure is typical in storytelling about school experiences.
中文： 在英語教育環境中，描述學生在中斷發生時正在做什麼是敘述課堂事件的常見方式。這種句子結構在講述學校經歷的故事時很典型。
EN： The Past Continuous tense (was/were + verb-ing) is used to describe an action that was in progress at a specific moment in the past. In this sentence, 'was sleeping' shows an ongoing background action.
中文： 过去进行时（was/were + 动词-ing）用于描述在过去某个特定时间点正在进行的动作。在此句子中，「was sleeping」表示一个正在进行的背景动作。
I was watching TV when the power went out.
停电时我正在看电视。
EN： The conjunction 'when' introduces a shorter, interrupting action in the Simple Past tense ('called') that happened while the longer background action ('was sleeping') was in progress.
中文： 连词「when」引导一个使用过去简单时（'called'）的短暂干扰动作，该动作发生在较长的背景动作（'was sleeping'）进行期间。
She was cooking dinner when the doorbell rang.
门铃响时她正在做晚饭。
EN： In English-speaking school contexts, 'called' can mean either calling someone's name in class (to answer a question) or calling them on the phone. Given the classroom context, it likely refers to the teacher calling on the student during a lesson or roll call.
中文： 在英語學校情境中，「called」可以指在課堂上叫某人的名字（要求回答問題），也可以指打電話。結合上下文，這裡很可能是指老師在課堂上點名或叫學生回答問題。
EN： The Past Continuous tense (was/were + verb-ing) is used here with the conjunction 'while' to describe two actions that were happening simultaneously in the past. Unlike 'when', which often introduces a sudden, short action, 'while' is typically used to connect two continuous, ongoing background activities.
中文： 过去进行时（was/were + 动词-ing）在此处与连词「while」结合使用，用来描述过去同时发生的两个持续性动作。与常接短暂、突然动作的「when」不同，「while」通常用于连接两个同时进行的背景活动。
My brother was playing video games while I was doing my homework.
我写功课时，我弟弟正在打电动。
EN： The Past Continuous tense (was/were + verb-ing) is used to describe an action that was in progress at a specific point in the past.
中文： 过去进行时（was/were + 动词-ing）用于描述在过去某个特定时间点正在进行的动作。
We were eating dinner when the phone rang.
电话响起时，我们正在吃晚餐。
EN： The conjunction 'when' introduces a short, sudden action in the Simple Past tense that interrupts a longer action in progress.
中文： 连词“when”引导一个使用过去时的短暂、突然动作，用以打断另一个正在进行的较长动作。
She was studying when the lights went out.
停电时，她正在看书。
EN： The Past Continuous tense ('was reading') is used to describe an action that was in progress at a specific moment in the past, often interrupted by another shorter action.
中文： 过去进行时（was reading）用于描述在过去某个特定时刻正在进行的动作，这个动作通常会被另一个较短暂的动作所中断。
I was cooking dinner when the guests arrived.
当客人到达时，我正在做晚餐。
EN： The conjunction 'when' introduces a sudden, shorter action in the Simple Past tense ('rang') that interrupts a longer ongoing action.
中文： 连词「when」引导一个使用过去简单时（rang）的短暂动作，用来表示中断了另一个正在持续进行的较长动作。
He was sleeping when the alarm went off.
当闹钟响起时，他正在睡觉。
EN： The Past Continuous tense (was/were + verb-ing) is used to describe an action that was in progress at a specific time in the past. It is often introduced by 'while' to show a longer background action.
中文： 过去进行时（was/were + 动词原形 + -ing）用于描述在过去特定时间点正在进行的动作。通常由“while”（当……时）引导，用来表示一个持续时间较长的背景动作。
While I was studying, the phone rang.
当我在读书时，电话响了。
EN： The Simple Past tense (e.g., 'dropped') is used for a completed action in the past. When combined with the Past Continuous, the Simple Past represents a shorter, interrupting event.
中文： 过去时（例如“dropped”）用于表示过去已完成的动作。当与过去进行时结合使用时，过去时通常表示一个较短的、中途插进来的事件。
She was cooking dinner when she burned her finger.
她正在做晚餐时烧伤了手指。
EN： The Past Continuous tense (was/were + verb-ing) is used to describe an action that was in progress at a specific moment in the past. Here, 'was talking' represents an ongoing background action.
中文： 过去进行时（was/were + 动词-ing）用于描述在过去某个特定时间点正在进行的动作。在这里，“was talking”（正在讲话）代表一个正在进行的背景动作。
They were studying when the lights went out.
停电时，他们正在看书。
EN： The conjunction 'when' is used to introduce a shorter, interrupting action in the Simple Past tense ('the class began') that occurred during the longer background action.
中文： 连词“when”（当……时）用来引导一个时间较短、具有干扰性质的过去时动作（“the class began”课堂开始），该动作发生在较长的背景动作进行期间。
I was cooking dinner when the phone rang.
电话响的时候，我正在做晚饭。
EN： Past Continuous Tense (Wh- Questions): Used to ask about an ongoing action that was happening at a specific point or period in the past. It is formed with 'Wh- word + was/were + subject + verb-ing'.
中文： 过去进行时（特殊疑问句）：用于询问在过去某个特定时间点或期间正在进行的动作。其结构为“特殊疑问词 + was/were + 主语 + 现在分词（动词原形 + -ing）”。
What were you watching on TV last night?
你昨天晚上在电视上看什么节目？
EN： Preposition 'during': Used to state that something happened within a specific period of time or throughout the course of an event. It is followed by a noun phrase.
中文： 介词“during”（在……期间）：用于表示某事发生在某个特定时间段或活动的过程中。后面接名词短语。
She fell asleep during the movie.
她在看电影时睡着了。
EN： In many English-speaking countries, schools regularly conduct 'drills' (such as fire drills, earthquake drills, or lockdown drills) to ensure students and staff know how to react safely in an emergency. It is a common part of the school routine.
中文： 在許多英語系國家的學校中，會定期舉行「drills」（防災演習，如消防演習、地震演習或防空避難演習），以確保學生和教職員知道在緊急情況下如何安全應對。這是學校日常生活中非常常見的一部分。
EN： The Past Continuous Tense (was/were + verb-ing) is used to describe an action that was in progress at a specific point in the past. In this sentence, 'were walking' shows an ongoing action during a past event (the drill).
中文： 过去进行时（was/were + 动词-ing）用于描述在过去特定时间点正在进行的动作。在本句中，「were walking」表示在过去某个事件（演习）期间正在进行的动作。
They were studying in the library when the lights went out.
停电时，他们正在图书馆里读书。
EN： Adverbs of manner (like 'calmly') describe how an action is performed. They are often placed after the verb or auxiliary verb to modify the action.
中文： 方式副词（如「calmly」）用来描述动作进行的方式。它们通常放在动词或助动词之后，用以修饰该动作。
She spoke softly to the crying baby.
她温柔地对着哭泣的婴儿说话。
EN： In Western schools, 'the field' usually refers to the grassy sports field or playground outside the school building. During emergency drills (like fire drills or earthquake drills), students are trained to walk 'calmly' and orderly to this designated safe assembly area.
中文： 在西方學校中，「the field」通常指校舍外的草地運動場或操場。在防災演習（如消防演習或地震演習）期間，學生們會接受訓練，要求「冷靜地」（calmly）且有秩序地走向這個指定的安全集結區。
EN： The Simple Past Tense is used to describe completed actions that happened at a specific time in the past. In this sentence, 'happened' is the regular past tense form of the verb 'happen', indicating the event occurred and was completed 'yesterday'.
中文： 一般过去时用于描述在过去特定时间已经完成的动作或发生的事件。在此句中，“happened”是动词“happen”的规则过去式变化，表示该事件在“昨天（yesterday）”发生并已结束。
An unexpected package arrived at my doorstep this morning.
今天早上一个意想不到的包裹送到了我家门口。
EN： The preposition 'during' is used to state that something happens within the time limit of an event, activity, or period. It is followed by a noun phrase (e.g., 'our class') rather than a clause.
中文： 介词“during”（在……期间）用于表示某事发生在某个事件、活动或特定时间段的过程之中。后面必须接名词或名词短语（例如“our class”），而非完整从句。
Please keep your phones silent during the movie.
电影放映期间请将手机调至静音。
EN： The Past Continuous tense (was/were + verb-ing) is used to describe an action that was in progress at a specific time in the past. In this sentence, 'were taking' indicates an ongoing activity (taking a test) during a past time frame (in the morning).
中文： 过去进行时（was/were + 动词-ing）用于描述在过去特定时间点正在进行的动作。在本句中，「were taking」表示在过去的时间段（早上）中正在进行的活动（进行测试）。
They were playing basketball when it started to rain.
开始下雨时，他们正在打篮球。
EN： Noun adjuncts (or noun modifiers) occur when a noun (like 'math') is used to modify another noun (like 'test'). Here, 'math' functions as an adjective to specify the type of 'test'.
中文： 名词修饰语是指一个名词（如 'math'）被用来修饰另一个名词（如 'test'）。在这里，「math」起到了形容词的作用，用来明确「test」（测试）的类型。
EN： The Past Continuous tense (was/were + verb-ing) is used to describe an action that was in progress at a specific moment in the past, often interrupted by a shorter action in the Simple Past tense.
中文： 过去进行时（was/were + 动词-ing）用于描述在过去某个特定时间点正在进行的动作，通常会被另一个较短的过去简单时动作所中断。
While I was cooking dinner, the phone rang.
我正在做晚饭时，电话响了。
EN： The subordinating conjunction 'while' is used to introduce a longer background action in the continuous tense, whereas 'when' is typically used for the shorter, interrupting action.
中文： 从属连词“while”用于引导进行时中较长的背景动作，而“when”则通常用于引导较短、具有打断性的动作。
The power went out while we were watching a movie.
我们正在看电影时，停电了。
EN： The Past Continuous Tense (was/were + V-ing) is used to describe an action that was in progress at a specific time in the past. In this sentence, 'was flying' and 'were laughing' describe two ongoing actions happening simultaneously.
中文： 过去进行时（was/were + 现在分词）用于描述在过去特定时间点正在进行的动作。在此句中，“was flying”和“were laughing”描述了同时进行的两个动作。
I was studying while my brother was playing video games.
当我在读书时，我弟弟正在玩电子游戏。
EN： The conjunction 'while' is used to connect two actions that were happening at the same time in the past, usually both in the past continuous tense.
中文： 连词“while”（当……的时候）用于连接两个在过去同时发生的动作，通常这两个动作都会使用过去进行时。
While she was cooking dinner, the phone rang.
当她正在做晚饭时，电话响了。
EN： The Past Continuous tense (was/were + verb-ing) is used to describe an action that was in progress at a specific moment in the past. In this sentence, 'was trying' shows an ongoing action that was happening during the classroom event.
中文： 过去进行时（was/were + 现在分词）用于描述在过去某个特定时间点正在进行的动作。在本句中，「was trying」表示在教室事件发生期间，老师正在进行的持续动作。
They were watching a movie when the power went out.
停电时，他们正在看电影。
EN： The verb 'try' followed by a to-infinitive (try + to + verb) means to make an effort to do something difficult. This contrasts with 'try + verb-ing', which means to do something as an experiment.
中文： 动词「try」后面接不定式（try + to + 动词原形）表示努力尝试做某件困难的事。这与「try + 动词-ing」（尝试做某事以看效果，即实验性质）不同。
I am trying to learn how to play the guitar.
我正试着学习如何弹吉他。
EN： The Past Continuous Tense (was/were + verb-ing) is used to describe actions that were in progress at a specific time in the past. Here, 'were standing' and 'were pointing' describe two ongoing background actions.
中文： 过去进行时（was/were + 动词-ing）用于描述在过去特定时间点正在进行的动作。在此句中，「were standing（正站着）」和「were pointing（正指着）」描述了两个同时在进行的背景动作。
They were studying while it was raining outside.
外面下着雨时，他们正在看书。
EN： The conjunction 'while' is used to connect two actions happening at the same time. It often contrasts two parallel activities in the past continuous tense.
中文： 连词「while（然而、当……的时候）」用于连接两个同时发生的动作。它常用于对比过去进行时中两个平行的活动。
I was cooking while my brother was washing the dishes.
我正在做饭，而我弟弟正在洗碗。
EN： The adverb 'Suddenly' is used at the beginning of a sentence to introduce an unexpected event, often shifting the narrative focus. It is followed by a comma.
中文： 副词「Suddenly」（突然间）常用于句首，用来引入出乎意料的事件，通常会转移叙事焦点。在句首使用时，其后通常会加上逗号。
Suddenly, the lights went out.
突然间，灯全部熄灭了。
EN： The phrasal verb 'land on' means to come down from the air and settle on a surface. It is followed by a noun phrase acting as the prepositional object.
中文： 短语动词「land on」表示从空中降落并停留在某个表面上。其后接名词短语作为介词的宾语。
The butterfly landed on her shoulder.
蝴蝶降落在她的肩膀上。
EN： The Past Continuous tense ('was sitting') is used to describe an action that was in progress at a specific moment in the past, often interrupted by a shorter action in the Simple Past tense ('looked').
中文： 过去进行时（was sitting）用于描述在过去特定时间点正在进行的动作，通常会被另一个使用过去简单时（looked）的短暂动作所中断。
I was reading a book when the phone rang.
电话响起时，我正在读书。
EN： The adverbial 'still' is used here as an adjective meaning 'motionless' or 'not moving', modifying the subject 'He' through the linking-like action of 'sitting'.
中文： 这里的 'still' 用作形容词，意思是「静止不动的」或「没动的」，修饰主语 'He'，表示坐着时的状态。
Please stand still while I take your photo.
我帮你拍照时请站着别动。
EN： The use of the coordinating conjunction 'and' to connect two independent clauses (complete sentences) that happen in chronological order. This creates a compound sentence.
中文： 使用并列连词「and」来连接两个按时间顺序发生的独立从句（完整句子）。这会形成一个并列句。
She finished her homework, and she went to bed.
她写完了功课，然后就去睡觉了。
EN： The phrasal verb 'fly out' (past tense: 'flew out') combines the verb 'fly' with the particle 'out' to indicate direction of movement.
中文： 短语动词「fly out」（过去式为「flew out」）结合了动词「fly」与小品词「out」，用来表示移动的方向（飞出去）。
A butterfly flew out of the window.
一只蝴蝶从窗口飞了出去。
EN： The Past Continuous tense (was/were + verb-ing) is used to describe an action that was in progress at a specific point in the past. It is often interrupted by a shorter action in the Simple Past tense.
中文： 过去进行时（was/were + 动词-ing）用于描述在过去特定时间点正在进行的动作。这类动作通常会被另一个使用过去简单时的短暂动作所中断。
What were you watching when the power went out?
停电的时候你正在看什么节目？
EN： The conjunction 'when' is used to introduce a single, completed event in the past (Simple Past) that interrupts a longer ongoing action.
中文： 连词「when」（当……时）用来引导一个发生在过去、已完成的单一事件（过去简单时），该事件通常会中断另一个正在持续进行的较长动作。
I was cooking dinner when the phone rang.
电话响的时候我正在做晚饭。
EN： In English-speaking cultures, asking 'What were you doing when...?' is a common, friendly way to start a conversation or show interest in someone's day, especially after an interruption or a shared event. Adding the person's name ('Emma') at the end makes the question feel more personal and direct.
中文： 在英語系國家中，詢問「What were you doing when...?」（當……時你正在做什麼？）是一種常見且友善的對話開頭方式，用來表達對他人生活的關心，特別是在發生某個插曲或共同事件之後。在句尾加上對方的名字（Emma）會讓對話顯得更親切且有針對性。
EN： The Past Continuous tense (was/were + verb-ing) is used to describe an action that was in progress at a specific moment in the past. In this sentence, 'was practicing' shows an ongoing activity in the past.
中文： 过去进行时（was/were + 动词-ing）用于描述在过去某个特定时间点正在进行的动作。在本句中，「was practicing」表示过去某个时刻正在持续进行的活动。
I was cooking dinner when you called.
你打电话来的时候，我正在做晚饭。
EN： The preposition 'at' is used with 'home' (at home) to indicate a specific location or state of being inside one's house.
中文： 介词「at」与「home」连用（at home），用来表示在自己家里的特定位置或状态。
They decided to stay at home because of the rain.
因为下雨，他们决定待在家里。
EN： The Past Continuous tense (was/were + verb-ing) is used here with 'while' to describe a longer, ongoing background action in the past ('was jogging').
中文： 过去进行时（was/were + 动词-ing）在此与连词 'while'（当……时）搭配使用，用来描述过去某个正在进行中的背景动作（'was jogging'，正在慢跑）。
While she was cooking dinner, the phone rang.
当她正在做晚餐时，电话响了。
EN： The Past Simple tense ('saw') is used to describe a shorter, completed action that interrupted or occurred during the longer background action.
中文： 过去简单时（'saw'，看见）用来描述在过去持续进行的背景动作中，突然发生或中断该动作的另一个短暂且已完成的动作。
While we were watching a movie, we heard a loud noise.
当我们正在看电影时，我们听到一声巨响。
EN： The Past Continuous tense (was/were + verb-ing) is used to describe an action that was in progress at a specific point in the past.
中文： 过去进行时（was/were + 动词-ing）用于描述在过去特定时间点正在进行的动作。
They were playing soccer when it started to rain.
开始下雨时，他们正在踢足球。
EN： The conjunction 'when' introduces a shorter, interrupting action in the Simple Past tense, which happens in the middle of a longer action (Past Continuous).
中文： 连词「when」引导一个较短、具干扰性质的过去简单时动作，该动作发生在较长动作（过去进行时）的进行过程中。
I was sleeping when the phone rang.
电话响的时候我正在睡觉。
EN： The Past Continuous tense (was/were + verb-ing) is used to describe an action that was in progress at a specific point in the past. It often sets the background scene.
中文： 过去进行时（was/were + 动词-ing）用于描述在过去特定时间点正在进行的动作。它通常用来设定故事或事件的背景。
I was cooking dinner when the phone rang.
电话响的时候，我正在做晚餐。
EN： The conjunction 'when' introduces a sudden, shorter action in the Past Simple tense that interrupts a longer action in progress (Past Continuous).
中文： 连词「when」（当……时）用来引导一个使用过去简单时的短暂、突然发生的动作，这个动作通常会中断另一个正在进行中的较长动作（过去进行时）。
They were playing soccer when it started to snow.
当开始下雪时，他们正在踢足球。
EN： The Past Continuous tense (was/were + V-ing) is used here with the conjunction 'while' to describe two continuous actions that were happening at the same time in the past.
中文： 过去进行时（was/were + V-ing）在此处与连词「while（当……之时）」连用，用来描述过去同时正在发生的两个持续性动作。
My dad was cooking while my mom was washing the dishes.
我爸爸在煮饭时，我妈妈正在洗碗。
EN： The conjunction 'while' is used to connect two clauses representing actions occurring simultaneously. It is usually followed by a continuous tense.
中文： 连词「while」用于连接两个表示同时发生之动作的从句。其后通常接进行时，但在口语中，若动作本身具有持续性（如 study），也可以接过去简单时。
While I was walking home, it started to rain.
当我正走路回家时，开始下雨了。
EN： The Past Continuous tense (was/were + verb-ing) is used here in a question format ('Were you sleeping...') to ask about an action that was in progress at a specific moment in the past.
中文： 过去进行时（was/were + 动词-ing）在此处以问句形式（Were you sleeping...）呈现，用来询问在过去特定时间点正在进行的动作。
Were you watching TV when I called?
我给你打电话的时候，你正在看电视吗？
EN： The conjunction 'when' introduces a time clause in the Simple Past tense ('when the bell rang') to describe a sudden, shorter action that interrupted the longer action in progress.
中文： 连词「when」引导过去简单时的时间状语从句（when the bell rang），用来描述一个突然发生、打断原本正在进行中动作的短暂事件。
I was cooking dinner when the lights went out.
停电的时候，我正在做晚饭。
EN： The Past Continuous tense (was/were + verb-ing) is used to describe an action that was in progress at a specific moment in the past. It often shows that the action was ongoing when another event interrupted it.
中文： 过去进行时（was/were + 动词-ing）用于描述在过去特定时间点正在进行的动作。它通常表示某个动作在另一个事件发生（或中断）时正在持续进行中。
I was reading a book when the phone rang.
电话响起时，我正在看书。
EN： The preposition 'about' is used after the verb 'dream' to indicate the subject or content of the dream.
中文： 介词 'about' 常用在动词 'dream'（做梦）之后，用来表示梦境的主题或内容。
She often dreams about traveling around the world.
她经常梦到环游世界。
EN： In school contexts globally, daydreaming about lunchtime or food during a boring or quiet class is a highly relatable and humorous sentiment shared among students.
中文： 在世界各地的學校情境中，學生在枯燥或安靜的課堂上「想著午餐吃什麼」或做關於食物的白日夢，是一個非常能引起共鳴且幽默的共同經驗。
EN： The past simple tense of the 'be' verb ('were') is used here to describe a state in the past. 'We' is a plural subject, so it takes 'were'.
中文： 这里使用 be 动词的过去简单时（were）来描述过去的状态。主语「We」（我们）是复数，因此搭配「were」。
They were tired after the long walk.
长途跋涉后，他们累了。
EN： The coordinating conjunction 'but' is used to connect two independent clauses that show a contrast. It is preceded by a comma when connecting two complete sentences.
中文： 对等连接词「but」（但是）用于连接两个表示对比的独立从句。当连接两个完整的句子时，前面通常会加上逗号。
It was raining, but we went out anyway.
下着雨，但我们还是出去了。
EN： The idiom 'time flies' is a common expression meaning that time seems to pass very quickly, especially when one is having fun or is busy. It is often used with 'when' to specify the circumstances under which time feels fast.
中文： 成语「time flies」（光阴似箭）是一个常用的表达方式，意思是时间过得非常快，特别是在玩得开心或忙碌的时候。它经常与「when」连用，以说明时间过得快的具体情境。
Time flies when you are having fun with friends.
和朋友一起玩乐时，时间总是过得特别快。
EN： The conjunction 'when' introduces an adverbial clause of time ('when you are doing something nice'), which describes the condition or time under which the main clause action ('time flies') occurs.
中文： 连词「when」引导时间状语从句（when you are doing something nice），用来修饰主句动作（time flies）发生的时间或条件。
I always listen to music when I am cleaning the house.
我打扫房子的时候总是听音乐。
EN： The phrase 'time flies' is derived from the Latin proverb 'tempus fugit'. It is a universally understood concept across cultures, reflecting the psychological phenomenon where our perception of time shortens when we are engaged in enjoyable activities.
中文： 「time flies」這個片語源自拉丁語諺語「tempus fugit」（時光飛逝）。這是一個跨文化通用的概念，反映了一種心理現象：當我們專注於令人愉快的活動時，對時間流逝的感知會變快。
重要单词附有 IPA 发音、定义、例句和互动式测验。
在本文中： 警报器
在本文中： 演练、演习
在本文中： 平静地、从容不迫地
在本文中： 突然地
在本文中： 静止不动的
在本文中： 终于、最后
在本文中： 鼓掌、拍手
在本文中： 练习
在本文中： 慢跑
在本文中： 闪烁、闪动
片语包含类型标示、双语定义、用法说明和例句。
To make a sudden loud noise, especially as a signal or warning.
（警报器、闹钟等）响起
Time passes surprisingly quickly.
光阴似箭、时间飞逝
To complete an exam or evaluation.
参加考试、测验