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.