宾语从句的时态
1. 如果主句的时态是一般现在时，宾语从句根据实际情况该用什么时态就用什么时态。
例：I dont think (that) you are right.
Please tell us where he is.
Can you tell me how I can get to the railway station?
2. 如果主句的时态是一般过去时，宾语从句只能用相应的过去时态（一般过去时，过去进行时， 过去将来时，过去完成时）。
例：He asked what time it was.
He told me that he was preparing for the sports meet.
He asked if you had written to Peter.
He said that he would go back to the U.S. soon.
3. 如果宾语从句所陈述的是客观真理，其时态常用一般现在时，此时不受主句时态的影响。
例：Our teacher said that January is the first month of the year.
Scientists have proved that the earth turns around the sun.
如果把上边的内容总结成为口诀课话，就是：
主现从随意；主过从过去；真理永一现。