陳述句變否定句的方法：
句中有動詞be( am ,is ,are ,was ,were),情態(tài)動詞（can / could ,may ,must ,will ,would 等）,助動詞（如完成時態(tài)中的HAS / HAD ）,變否定句時直接在這些詞后加NOT ；否則要加助動詞Do ,Does （主語第三人稱單數(shù)）,Did （一般過去時）,原來的動詞要還原；另外,句中有SOME 是一般改為ANY ,如果有AND 要改為OR,（因?yàn)榉穸ň渲械牟⒘幸肙R）already 改為yet（且放在句末）；祈使句的否定句是直接在句首加Don’t ;
( 如Open the doo r,please .-> Don’t open the door ,please .) 不定式的否定句是在不定式前加NOT ,如 She asks the boy not to play in the street .
He is a student .-> He isn't a student.
There are some flowers in the room .-> There aren't any flowers in the room .
加油!不明白再問!1 Open the doo r,please .->Don’t open the door ,please . 2 Sheasks the boy not to play in the street . 3 He is a student .->He isn't a student.4 There are some flowers in the room .->There aren't any flowers in the room .5 He has finished his homework .->He hasn't finished his homework.6 He can swim .->He can't swim .7 He went to the park last Sunday. ->He didn't go to the park last Sunday.8 I like English .->I don't like English.9 She likes singing .->She doesn't like singing .10 They will finish the work tomorrow.->They won't(= will not )finish the work tomorrow.