一定情况下宾语从句的时态必须和主句的时态保持一致：
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。
1. 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. 她说她在上网。
He told me that he knew the computer technology very well. 他对我说他精通电脑技术。
2. 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. 他不知道他们到这里来的目的。
3. 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. 吉姆告诉我他将到南方度假。
