By the time when the course comes to an end,（ ）a lot about computer.

题目

By the time when the course comes to an end,（ ）a lot about computer.
（we'll have learned / we'll learn / we're learning / we have learned）
这题应该选什么,说出正确答案的理由和其他三个选项为什么不选的理由,

答案

填 we'll have learned
根据句意,the cours还没有完成,所以the course comes to an end 是将来的事情,by+将来每一个时间点,是用将来完成时的标志,所以要用将来完成时will have done.