since引导的时间状语何时用现在完成时,现在完成进行时

题目

since引导的时间状语何时用现在完成时,现在完成进行时
My spoken English has since I came to this school in August. A.raised a lot B.been improved a lot C. raised a lot of D.improved a lot
汗。。。答案选D，用的现在完成时

答案

Sorry,for my misunderstanding and misleading advice.
I thought B says " been improving a lot." in the Perfect continous tense.But it isn't.
In this case,my judgement should be changed like this:
1.Both B & D are correct.
2.In terms of the best choice,it should be D.
Because in most cases,we don't use the passive voice when we say,sth gets better = improve.
sth + be improved,the passive voice,is also possible,when you especially emphasizes the passive action,which sound a little bit unnatural.