Have you finished ( ) your letters.A.writing B.to write C.write D.wrote 要写原因
问题描述：
Have you finished ( ) your letters.A.writing B.to write C.write D.wrote 要写原因
答
A. writing
这里要用作动词，因为writing letters 是个名词，表示“写信”这个名词。
答
A
finish doing 完成某事