Are they good at ( 用swim的正确形式填空
问题描述:
Are they good at ( 用swim的正确形式填空
答
at 是介词,介词后加名词代词动名词,所以是swimming
答
Are they good at (swimming)?
答
swimming
at是介词 后面必须加名词
答
Are they good at ( swimming)?