of which的用法

题目

of which的用法
We have gathered nearly 100,000 quilts,_____up to half have gone to flood-hit areas.
A.with which B.in which C.for which D.of which
【解答】选D.这里的which指的是,nearly 100,000 quilts（被褥）,也就是说,后半句的主语是在这nearly 100,000 quilts里面的up to half.（后半句的主语是在这nearly 100.000 quilts 里面的up to half)怎么理解吖?

答案

正确答案是Dwe have gathered nearly 100,000 quilts,of which up to half have gone to flood-hit areas.在这里,把后面句子调整成up to half of which have gone to flood-hit areas.这样就看出up to half的用法了,...