英语中有3个基本助动词:1.be 2.do 3.have
be+doing表进行
be+done表被动
be+to do表既定计划
be+about表既定计划即可实现
be+going+to do表目前临时计划或根据迹象推测
be+used+to +doing表过去无现在有的习惯
do+do表强调
have+done表完成
have+to do表迫不得已不得不
had better+do表威胁
what did you do yesterday?是do+do型 前移构成疑问
I did not like(run,还是ran) 应该是i didn't run