使用疑问词进行提问和问答
使用疑问词：when，where，who，what，how
He bought three books yesterday. （bought: [bɔːt]）
谁买？
1. Who bought three books yesterday?
买什么？
2. What did he buy(用原型) yesterday? [对于不是主语，提问要使用助动词 + 原型]
什么时间买？
2. When did he buy three books?
[不是主语，要使用 助动词/be动词 提问 + 原型]
使用疑问词进行提问和回答
how long，how far，how often，why + 助动词
1. They have been in China for three years.
How long have they been in China? [多久？完成时]
2. It is about 4 kilometers from Beijing to Xian.
How far is it from Beijing to Xian?
3. They come to visit me once a week.
How often do they come to visit me? [多久，频度]
4. She came late, beacuse she missed the bus.
Why did she come late?
[疑问句中是否含有助动词，情态动词，如果有的话，动词要以动词原形出现，另外就是what which who 直接作主语时，后面的动词根据时态而定。]
该笔记整理于崔荣容老师的视频讲解：https://www.bilibili.com/video/av2639206