1.It wasn't until nearly a month later _____ I recevied the manager's reply.

1.It wasn't until nearly a month later _____ I recevied the manager's reply.
A.since B.when C.as D.that
我选的是B.不过这还不是最关键的.这句话我翻译的不是很通顺.希望高手们把这句话的意思翻译出来、再告诉我为什么选D、
2.It was after he got what he had desired ______ he realized it was not so important.
A.that B.when C.since D.as
这一题的答案是A.我选的是B.（真囧).句意我也不是太懂.跟上一题同样的解决办法吧.
3.--The duty of projeat Hope is to help poor children,isn't it?
--Yes,it has built many schools ______ those children can study happily.
这一题的答案是D,我选的是A.哦不.意思我懂,但是我不懂答案的意思.
就这3题.
一定会追加分数的、
呃.真是不好意思诶、本来打了的.咋就给我删了?.
A.where B.when C.which D.that