she will sing a song____she is asked.
题目
she will sing a song____she is asked.
A.if B.unless C.for D.since 请问选哪一个 为什么呢? 谢谢
答案
if
原因不太好说,语感是if
unless
应该这样说：she wouldn't sing a song ,unless she were asked.
for since
应该这样说：she sung a song,for/since she had been asked.
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