By the time the course ends,a lot _____ about the United States.A.will have been learned B.will have learned C.are learned D.have been learned 为什么不选D
问题描述：
By the time the course ends,a lot _____ about the United States.
A.will have been learned B.will have learned
C.are learned D.have been learned
为什么不选D
答
by 与时间状语连用时，意思为:到什么进为止，一般都用完成时态
答
是A嘛```?
答
应该是A.
a lot代指很多知识,所以用被动.
by加将来时,用将来完成时.
所以选A
意思是：到这个课程结束的时候,很多关于美国的知识将被学到（你将会学会很多关于美国的知识）.