(1)当句子中有be动词或情态动词时，则把be动词或情态动词(can,could等等)提到主语的前面变成疑问句;
在be动词或情态动词后面加not变成否定句.
例：①陈述句：She is a student.
疑问句→ Is she a student?
否定句→ She is not a student.
②陈述句：I can swim.
疑问句→ Can you swim .
否定句→ I can not swim.
(2) 当句子中即没有be动词，也没有情态动词时，则在主语前加助动词do (you,以及复数), does(单数she,he,it)变成问句;
在主语后谓语动词前加助动词don’t(I,you,以及复数), doesn’t(单数she,he,it)变成否定句，助动词后的动词要变成动词原形。
例：①陈述句：We get up at 7:00 every morning.
疑问句→Do you get up at 7:00 every morning?
否定句→We don’t get up at 7:00 every morning.
②陈述句：She has a little brother.
疑问句→ Does she have a little brother?
否定句→ She doesn’t have a little brother