现在完成时和过去完成时可以互换吗?

1个回答

  • 宾语从句的时态

    一般情况下宾语从句的时态必须和主句的时态保持一致:(1)如果主句的谓语动词是一般现在时或一般将来时,宾语从句中的谓语动词可根据意义的需要,使用任何一种时态.如:I don’t know if he arrived yesterday. (2) 如果主句的谓语动词为一般过去时,从句应用相应的过去时态. A.如果主句中的谓语动词所表示的动作与从句的动作同时发生,则从句应用过去进行时或一般过去时.如: She said that she was working on the Internet. B.如果从句的动作发生在主句的动作之前,则从句应用过去完成时.如: He didn’t know what they had come here for. C.如果从句的动作发生在主句的动作之后,则从句应用过去将来时.如: Jim told me he would spend his holidays in the south.