题目内容：

____a boy,he used to help his father on the farm.A.Being B.As 选A可以吗

优质解答

只能选as
being a boy表示 现在正是小孩 跟used to help不对应
as a boy表示when he was a boy
另外还要明白used to do不仅仅表示过去常做 同时还表示现在已经不做了