The ‘silent killer’: what you need to know about heatwaves
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EN: The sentence begins with a nominal relative clause (also called a free relative clause) introduced by 'What'. Here, 'What' functions as 'the thing(s) that', acting as the subject of the entire title/sentence. It is a common way to introduce a topic or highlight essential information.
What you need to bring is a valid ID.
EN: The preposition 'about' is used to indicate the subject matter or topic of the knowledge. It connects the verb phrase 'need to know' with the noun 'heatwaves' to specify what the knowledge is concerning.
I want to learn more about climate change.
EN: The Present Perfect Tense (have/has + past participle) is used here ('have become', 'has changed') to describe actions or states that started in the past and have a direct connection or relevance to the present moment.
Global temperatures have risen significantly over the last century.
EN: The conjunction 'as' is used to indicate that two trends or actions are happening at the same time, often showing a parallel development or a cause-and-effect relationship (meaning 'while' or 'because').
As the sun went down, the temperature began to drop.
EN: The verb 'call' can take a direct object followed by an object complement (Noun Phrase) to express 'to name or describe someone/something as a particular thing'. The structure is: call + Object + Object Complement.
Many people call the lion the king of the jungle.
EN: The subordinating conjunction 'because' is used to introduce a subordinate clause of reason (adverbial clause of cause), explaining why the action in the main clause happens.
She stayed at home because it was raining heavily.
EN: The term 'silent killer' is commonly used in medical and public health contexts to describe conditions or environmental factors (like high blood pressure, carbon monoxide, or extreme heat) that cause severe harm or death without obvious, immediate, or dramatic symptoms.
EN: The phrase 'An estimated' is used before a number or quantity to show that the figure is not exact but is a calculated approximation. It functions as an adjective modifying the noun phrase.
An estimated ten thousand people attended the outdoor concert.
EN: The prepositional phrase 'die from' is used to specify the direct cause of death, such as a disease, hunger, or environmental factors (e.g., heat-related causes).
Many wild animals die from lack of food during harsh winters.
EN: The phrase 'heat-related causes' reflects a growing public health and meteorological consensus. In many Western countries, deaths during heatwaves are often indirect (e.g., heart failure triggered by heat), so medical and environmental reports use 'heat-related' to capture the broader, systemic impact of extreme weather rather than just direct heatstroke.
EN: Comparative Adjectives (higher than): Used to compare two things, people, or quantities. For short adjectives, we add '-er' to the adjective and follow it with 'than'.
The temperature today is higher than it was yesterday.
EN: Past Participle as Post-modifier (caused by): A past participle phrase can be placed directly after a noun to function as an adjective, describing or defining the noun. It has a passive meaning (equivalent to a shortened relative clause: 'which are caused by').
The damage caused by the storm was severe.
EN: Passive Voice with 'be + past participle' (is listed): Used when the focus is on the action or the receiver of the action, rather than the doer. Here, 'heat' is the receiver of the action 'list'.
The results are published on the school website every month.
EN: Adverbs of Frequency (rarely): Adverbs that describe how often something happens are typically placed before the main verb (listed) but after the auxiliary or 'be' verb (is).
She is rarely late for her morning classes.
EN: The structure 'This is because...' is used to introduce a clause that explains the reason for something mentioned previously. 'Because' acts as a subordinating conjunction introducing an adverbial clause of reason.
He missed the train. This is because he overslept.
EN: The relative pronoun 'that' introduces a defining relative clause (adjective clause) modifying the noun phrase 'indirect killers'. The verb 'make' in this clause is followed by an object ('existing illnesses') and an object complement ('worse') to describe a change in state.
She bought a device that makes daily tasks easier.
EN: In public health and climate science discourse, the term 'indirect killer' is increasingly used to describe environmental factors like heatwaves. Unlike direct causes of death (such as accidents), heat-related deaths often manifest as heart or kidney failure, making the underlying climate factor less visible in official statistics.
EN: The preposition 'from' is used after the verb 'die' to indicate the specific cause of death (e.g., a disease, hunger, or old age). This is a common collocated pattern: 'die from + cause'.
Many people in history died from the flu before modern medicine was developed.
EN: The non-defining relative clause starting with ', which' is used to add extra, non-essential information about the preceding nouns ('diseases of the heart, lungs, or kidneys'). It is separated by a comma and uses 'which' as a relative pronoun.
He decided to avoid caffeine, which helped him sleep much better at night.
EN: Apposition (Appositive Noun Phrase): An appositive is a noun or noun phrase that sits next to another noun to rename or describe it. In this sentence, 'a public health expert' is an appositive phrase that provides more information about 'Doctor Maria Santos'. It is set off by commas.
Mr. Chen, a high school teacher, loves reading history books.
EN: Noun Clause as Direct Object: A noun clause is a dependent clause that functions as a noun. Here, the clause 'that many people do not realize how dangerous a heatwave can be for their health' acts as the direct object of the reporting verb 'has said'. Within this, 'how dangerous a heatwave can be for their health' is an indirect question functioning as another noun clause (the object of 'realize').
She believes that we should protect our environment.
EN: The collocation 'put stress on' means to place pressure or strain on someone or something. 'Stress' is an uncountable noun here, and it is often modified by adjectives like 'great' or 'severe'.
The financial crisis put great stress on their marriage.
EN: The adverb 'especially' is used to single out one person, thing, or situation as being more important or fitting a description better than others. It is often followed by a prepositional phrase (e.g., 'on...').
I love eating fresh fruit, especially in the summer.
EN: The semi-modal verb 'have to' is used to express strong obligation or necessity imposed by external circumstances (in this case, the physical demand of rising temperatures). It is followed by the base form of the verb ('work').
We have to leave early to catch the train.
EN: The causative structure 'keep + object + adjective' (keep the body cool) is used to describe maintaining a person or thing in a specific state or condition.
Please keep the door open to let some fresh air in.
EN: The relative clause starting with 'who' is used to modify the noun 'people'. 'Who' acts as the subject relative pronoun within the clause 'who already have chronic illnesses'.
The teacher praised the students who finished their homework early.
EN: The modal verb 'can' is used here to express possibility, indicating that the added strain has the potential to be fatal under certain conditions.
Extreme weather can cause severe damage to local infrastructure.
EN: The 'There + be' structure is used to state the existence of something. In this sentence, 'There are' is used because the subject 'secondary dangers' is plural. 'Also' is an adverb placed after the verb 'are' to add information.
There are also many benefits to exercising regularly.
EN: Non-defining relative clauses are introduced by 'which' (preceded by a comma) to provide extra, non-essential information about the noun before them (in this case, 'secondary dangers').
He bought a new car, which cost him a lot of money.
EN: The phrase 'put pressure on' is a common collocation meaning to place a burden, stress, or demand on someone or something. 'Extra' acts as an adjective modifying the noun 'pressure'.
The upcoming exams put a lot of pressure on the students.
EN: The modal verb 'can' is used here to express possibility, indicating that these problems have the potential to cause strain on the healthcare system.
Loud noises can cause permanent damage to your hearing.
EN: The Present Perfect Tense ('have + past participle') is used here to describe an action that happened at an unspecified time in the past and has relevance to the present. The adverb 'also' is placed between the auxiliary verb 'have' and the main verb 'warned'.
Researchers have also found that exercise improves sleep quality.
EN: A noun clause starting with the conjunction 'that' functions as the direct object of the verb 'warned'. It contains a complete sentence structure (subject + verb + complement) that expresses the content of the warning.
She warned that the roads would be icy after the storm.
EN: Adverbial Clause of Time introduced by 'When': This clause sets the condition or time frame under which the main action occurs. In this sentence, 'When days are too hot and nights do not cool down enough' acts as the time clause, modifying the main clause.
When the rain stops, we will go for a walk in the park.
EN: Adverb 'enough' modifying a verb: The word 'enough' is used as an adverb meaning 'to the required degree'. When modifying a verb (like 'cool down'), it is placed after the verb or verb phrase.
He did not practice enough to win the competition.
EN: The verb 'compound' is used as a transitive verb meaning to make something bad worse, or to intensify a negative situation. It is often followed by nouns like 'damage', 'problem', or 'difficulty'.
The heavy rain compounded the traffic problems in the city.
EN: The relative clause 'that is done during extremely hot days' uses the relative pronoun 'that' as the subject of the passive voice verb 'is done'. This clause modifies the noun 'damage', describing what kind of damage is being referred to.
The work that is done by volunteers is highly appreciated.
EN: The verb 'describe' is commonly used with the pattern 'describe A as B', which means to portray or define someone or something as having a particular character or identity. Here, 'A' is the object ('nights above 20 degrees Celsius') and 'B' is the object complement ('tropical nights').
The guide described the historic building as a masterpiece of architecture.
EN: The prepositional phrase 'above 20 degrees Celsius' acts as an adjective phrase modifying the noun 'nights'. 'Above' is used here to indicate a temperature higher than a specific limit.
EN: The term 'tropical night' (Tropennacht in German, nuit tropicale in French) is an official meteorological term used in Europe to describe a night when the temperature does not fall below 20 degrees Celsius. Due to climate change, these nights are becoming increasingly common in temperate European regions, posing health risks as human bodies cannot cool down and recover from daytime heat.
EN: The Present Perfect Tense (have/has + past participle) is used here to describe a state or action that started in the past and continues to have relevance or exist in the present. In this sentence, 'have become' indicates a gradual change that has occurred over time up to the present.
Global temperatures have risen significantly over the past century.
EN: 'Because of' is a multi-word preposition used to introduce the reason for something. It must be followed by a noun, pronoun, or noun phrase (like 'climate change'), unlike 'because' which is a conjunction followed by a full clause (subject + verb).
The flight was delayed because of the heavy rain.
EN: In recent years, European meteorologists have increasingly focused on 'tropical nights' (nights where the temperature does not drop below 20°C) as a key indicator of climate change. These nights are culturally and socially significant because traditional European housing often lacks air conditioning, making warm nights a direct threat to public health.
EN: The 'There + be' structure is used to indicate the existence of something. In this sentence, 'There are' is used because the subject 'several protection measures' is plural.
There are many ways to solve this problem.
EN: The relative pronoun 'that' introduces a defining relative clause ('that people can take...') modifying the noun phrase 'several protection measures'. In this clause, 'that' functions as the direct object of the verb 'take'.
These are the books that you ordered yesterday.
EN: The verb 'recommend' can be followed directly by a gerund (V-ing) to suggest an action. When multiple actions are recommended, they must be in parallel structure, meaning all actions should use the gerund form (drinking, staying, and wearing).
The doctor recommends exercising daily and eating more vegetables.
EN: Parallel structure (parallelism) is used to connect words, phrases, or clauses of equal grammatical rank. In this sentence, three gerund phrases are joined by commas and the coordinating conjunction 'and' (A, B, and C).
She enjoys reading books, listening to music, and playing tennis.
EN: Apposition (同位語): A noun phrase placed next to another noun to identify or explain it. Here, 'a climate researcher' is an appositive that provides more information about 'Professor James Liu'. It is set off by commas.
Mr. Chen, a high school teacher, loves reading books.
EN: Adverbial Clause of Purpose with 'so that' (表示目的的狀語從句): 'So that' is a conjunction used to introduce a clause expressing purpose or result, often followed by modal verbs like 'can', 'could', or 'may'.
She saves money so that she can buy a new laptop.
EN: In climate science and public health, 'vulnerable people' typically refers to the elderly, young children, outdoor workers, and individuals with pre-existing medical conditions (like heart or kidney disease) who are disproportionately affected by extreme weather events.
EN: Present Perfect Passive Voice ('have been urged'): This structure is used to describe an action that started in the past and continues to have relevance now, with the focus on the receiver of the action (Governments) rather than the doer. It is formed by 'have/has + been + past participle'.
Local communities have been urged to prepare for the upcoming storm.
EN: Infinitive of Purpose ('to reduce'): The 'to-infinitive' is used here to express purpose or intention, answering the question 'why'. It is a shortened form of 'in order to'.
She saved money to buy a new laptop.
EN: In recent years, 'heat action plans' have become a vital policy tool for municipal and national governments worldwide. These plans typically include early warning systems, opening public cooling centers, and adjusting outdoor work hours to protect vulnerable populations during extreme heatwaves.
Key vocabulary words with IPA pronunciation, definitions, example sentences, and interactive quizzes.
Phrases with type tags, bilingual definitions, usage notes, and example sentences.
A disease or condition that causes death without showing obvious symptoms beforehand.
Periods of time when the electricity supply to a particular area is interrupted.
Nights when the temperature does not fall below 20 degrees Celsius.
People who are easily harmed, influenced, or attacked, such as the elderly, children, or those with illnesses.