by the time the course ends,___a lot about britaina we'll learn b we are learningc we have learnt d we'll have learnt
问题描述：
by the time the course ends,___a lot about britain
a we'll learn b we are learning
c we have learnt d we'll have learnt
答
选D，
By the time 表示 “当…的时候”
By the time the course ends, we will have learnt a lot about market money
像此类题我们通常会做成过去完成时，但这样是错误的
记住这句话：
从句用一般时，主句用将来时。
答
by the time ：到…时候为止;
到…时候为止
【情况一】：通常引导一个时间状语从句，表示“到……的时候为止”主句则表示在此时间之前某个事件已完成。值得注意的是，当从句用过去时时，主句通常用过去完成时。
例如： By the time l got to the station，the train had already gone。
【情况二】：如果从句是一般现在是，也就意味着这件事还没发生，那么此时，主句我们用将来完成时。
所以此题选择D选项
答
选 D we'll have learnt 将来完成时
by the time the course ends,we'll have learnt a lot about britain.
到这门课程结束的时候,我们将会学到很多关于英国的知识.