陈述句变疑问句如下：
1、观察句中是否有be动词（am,is,are,was,were）、情态动词（can,must,will,may等），如果有，将其提到句首，句末打上问号即可。
例：I am a teacher.→Are you a teacher?
It is sunny today.→Is it sunny today?
You are a student.→Are you a student?
Bill can play the piano.→Can Bill play the piano?
They must go to school early.→Must they go to school early?
I will go with you.→Will you go with me?
2、如果句中没有be动词或情态动词，则根据谓语动词的形式借助do的相应形式(do, does, did)放在句首。具体方法是：如果谓语动词是原形，则借助do；如果谓语动词是一般现在时第三人称单数形式，则借助does；
如果谓语动词是一般过去式，则借助did。此类改为一般疑问句时，本来句中没有，需要借助的动词就称为助动词。值得注意的是，借助does或did后，原句的谓语动词要变回原形。
例：They go to school by bus.→Do they go to school by bus?
Robert gets up at 7:30 every day.→ Does Robert get up at 7:30 every day?
The students saw a film yesterday.→Did the students see a film yesterday?
陈述句变一般疑问句应注意的事项如下：
陈述句变成一般疑问句除了遵循上述规则以外，还应注意下列几点：
1、如果陈述句中有第一人称，则变问句时要变为第二人称。
例：I usually have lunch at school.→Do you usually have lunch at school?
2、如果陈述句中有some, 则变问句时往往要变成any.
例：There is some water in that bottle.→Is there any water in that bottle?
3、如果陈述句中有并列连词and，改为一般疑问句需要改为or.
例：I like tea and coffee.→ Do you like tea or coffee?
4、如果句中含有实义动词have且表示“有”时,除借助do外，也可将其直接提到句首。
例：I have some friends in America.→Have you any friends in America?→Do you have any friends in America?
5、另外要注意，陈述句改为一般疑问句时，句首字母要大写，句号需要改为问号。