be动词，情态动词，助动词do/does的用法区别及练习1.由连系am，is，are构成的句子：变一般疑问句时把am，is，are提到句子的前面，句尾用问号即可。变否定句时直接在am，is，are后面加not即可。例如：肯定句:He is a student.一般疑问句: Is he a student?否定句: He is not a student.画线提问:对he提问: Who is a student?对a student提问: What is he? or What does he do?2.由情态动词can, may, should等构成的句子:变一般疑问句时把can,may,提到句子的前面,句尾用问号即可.变否定句时直接在can,may,后面加not即可.例如:肯定句: She can swim.一般疑问句: Can she swim?否定句: She can not swim.画线提问:对she提问: Who can swim?对swim提问: What can she do？3.由
