疑问词：
when（什么时候），where（哪），who（谁），
what（什么），how（怎么），howlong（多长时间），
how far（多远），how ofen（多长时间一次），why（为什么）
1、He bought three books yesterday.他昨天买了三本书。
Who bought three books yesterday?谁昨天买了三本书？
What did he buy yesterday?他昨天买了什么？
当对句子的宾语进行提问的时候要使用助动词，或者原句中有助动词时将助动词提到疑问词后面，动词变为原型（bought变为buy）
When did he buy three books?他什么时候买了三本书？
2、They have been in China for three years.
How long have they been in China?
3、It is about 1000 kilometers from Beijing to Xi'an.
How far is it about from Beijing to Xi'an?
4、They come to visit me once a week.
How ofen do they come to visit me?
5、She came late,because she missed the bus.
Why did she come late?
总结：
疑问词要放在句首，如果提问对象是主语句子的其他成分按照陈述句的顺序保持不变
提问对象不是主语要使用助动词帮助构成疑问句
练习：
They wanted to go to Shanghai by air.他们想坐飞机去上海。
Who wanted to go to Shanghai by air?谁想做飞机去上海？
Where did they want by air?他们想坐飞机去哪？
How did they want to go to Shanghai?他们想怎么去上海？
他们学汉语多长时间了？How long have they learned Chinese? 现在完成时助动词用have
你多长时间看一次电影？How ofen do you watch movies?一般现在时主语非第三人称助动词用do
你的家离学校多远？How far is it from your house to your school？
