题目内容：

The old man whose son is in the navy used to be carpenter.
请问,used to be carpenter,为什么不是used to be a carpenter.

优质解答

1.按照语法的规则,应该是有个a,如,I want to be “a” teacher when I grow up.2.按照意义：儿子在海军的那位老人过去“是个”木匠.也是该有个a的,3.The old man （whose son is in the navy） used to be carpenter...