(1)变一般疑问句：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)提到主语的前面，
(口诀：一调二变三问号);
(2)变否定句：在be动词或情态动词后面直接加not变成否定句. (be后not莫忘记)
例：①陈述句：She is my sister..
疑问句 Is she your sister? Yes, I am./ No, Im not.
否定句 She is not my sister.
②陈述句：I can play soccer.
疑问句 Can you play soccer? Yes,Ican./ No, I cant.
否定句 I can not /cant play soccer.
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