问题
选择题
-- Tommy, your mum has been out without glasses!
-- Well, take it easy. she is back home for them.
A．It is long before that
B．It won't be long since
C．It won't be long before
D．It will be long before
答案
答案：C
题目分析：考查句型：It will be +一段时间+before…,要多长时间才…，句意：--Tommy，你妈妈没带眼镜就出去了，没关系，不要多久她就会回来拿的。选C。
点评：固定句型：It was+一段时间+before…，要多久…就（才）…，容易混淆的句型是it is/has been 一段时间since从句（过去时）；自从…以来，已经有一段时间了。