GUIDE深度 · Deep dive
反意疑问句和条件句
反意疑问句前肯后否、前否后肯，助动词与主语一致。条件句分零/一/二/三：零条件用现在时，一条件 if+现在时/will，二条件 if+过去式/would，三条件 if+had done/would have done。
反意疑问
She is happy, isn't she?
They went home, didn't they?
He can swim, can't he?
条件句
If it rains, we will stay.
If I were rich, I would travel.
If he had studied, he would have passed.
常见问题
第二条件句一定用 were 吗？
正式英语中 if I were 更标准。
第三条件句能省 had 吗？
不能；had + 过去分词是核心。