题干
—I’m sure Andrew will win the first prize in the final.
—I think so. He ________ for it for months.
—I think so. He ________ for it for months.
A：is preparing
B：was preparing
C：has been preparing
D：had been preparing
答案(点此获取答案解析）
C
、 
的矩形纸片的四个角都剪去一个边长为 
的正方形．