While 可以表示在某段时间内，也可以在比较事实时表示“而”。第一种意思连接同时发生的动作：I fell asleep while I was watching the film。第二种意思在一句话里对比两个事实，作文和图表描述很常用：Prices rose in the north, while they fell in the south。
你会怎样使用 while？
写一句英语，检查连接词与意思是否匹配，并查看修改建议。
本次检查比平时稍久，完成后反馈会自动显示在这里。
while + clause (= during the time that); while + -ing; clause, while + clause (= whereas); While + clause, + clause (= although)
- Could you feed my cat while I'm away on a business trip next week?
- In 2010 most people paid in cash, while by 2020 cards had become far more popular.
- My older sister loves big noisy parties, while I'd rather meet one friend for coffee.
修改原因
修改前I'll read your report while I'll be on the train tomorrow.
修改后I'll read your report while I'm on the train tomorrow.
整句在谈明天，所以容易觉得 while 后也该加 will。但 while 表示时间、指向未来时，像 when 和 until 一样，通常使用现在时。修改只把 I'll be 换成 I'm；tomorrow 和主句已经说明时间在将来。
句首的 while 也常表示“虽然”，先承认一部分观点，再提出转折：While online shopping is convenient, it has hurt many small shops。这种开头适合用于作文引入观点。表示时间时，不要混淆 while 和 during：during 后接名词，如 during the flight；while 后接带动词的从句，如 while we were flying。
动手练习
Someone stole my wallet ___ I was waiting for the bus outside the station.
查看答案
while — 偷钱包和等公交同时发生，需要表示“在……期间”，所以选 while。Whereas 有时被解释成 while，但它只对比事实，不表达同时发生。
比较工作日与周末的早晨。在一个含 while 的句子中，说明这两种早晨分别会做什么。
On weekdays I leave home at seven and grab a coffee on the way, while at weekends I stay in bed until ten.
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