(1)當(dāng)句子中有be動(dòng)詞或情態(tài)動(dòng)詞時(shí)，則把be動(dòng)詞或情態(tài)動(dòng)詞(can,could等等)提到主語(yǔ)的前面變成疑問句;
? ? 在be動(dòng)詞或情態(tài)動(dòng)詞后面加not變成否定句.
例：①陳述句：She is a student.
? ? ? ? 疑問句→ Is she a student?
? ? ? ? 否定句→ She is not a student.
? ? ?②陳述句：I can swim.
? ? ? ? 疑問句→ Can you swim .
? ? ? ?否定句→ I can not swim.
(2) 當(dāng)句子中即沒有be動(dòng)詞，也沒有情態(tài)動(dòng)詞時(shí)，則在主語(yǔ)前加助動(dòng)詞do (you,以及復(fù)數(shù)), does(單數(shù)she,he,it)變成問句;
? ? ?在主語(yǔ)后謂語(yǔ)動(dòng)詞前加助動(dòng)詞don’t(I,you,以及復(fù)數(shù)), doesn’t(單數(shù)she,he,it)變成否定句，助動(dòng)詞后的動(dòng)詞要變成動(dòng)詞原形。
例：①陳述句：We get up at 7:00 every morning.
? ? ? ? 疑問句→Do you get up at 7:00 every morning?
? ? ? ? 否定句→We don’t get up at 7:00 every morning.
? ? ?②陳述句：She has a little brother.
? ? ? ?疑問句→ Does she have a little brother?
? ? ? ?否定句→ She doesn’t have a little brother