by the time主句用一般现在时，从句用什么时态 主句用一般过去，从句用什么时态

by the time主句用一般现在时，从句用什么时态 主句用一般过去，从句用什么时态

有关by the time 的时态：
1.后接表示现在的时间，用现在完成时。 如 By the time of this term, we have learned 5000 words.
2.后接表示将来的时间，用一般将来时或将来完成时。 如 By the time 2012, we will learn 5000 words. (一般将来时) 或By the year 2012, we will have learned 5000 words. (将来完成时)
3.后接表示过去的时间，用过去完成时。如 I hadn’t found a job by the time my classmates all found their jobs.

这个词组常用来指到某一点时间为止，主句常用完成时态。具体如下： 1）从句用一般现在时，主句用将来完成时（will have done)。 bythe time i graduate next year, i will have lived here for 5 years. 到明年毕业时，我就在这里呆了五年了。 2）从句用一般过去时，主句用过去完成时。 e.g.bythe time he was 12, he had traveled to more than 30 countries to get his diseases cured. 到12岁为止，他已去过三十多个国家治病。