29._______the road,be careful.
问题描述：
29._______the road,be careful.
A.While
crossing B.When
cross C.Crossed D.
Being crossed
答
选A.
解析：这个是祈使句,暗含的主语是you,You 和cross the road 是主谓关系,不能用被动,排除C、D.A正确,这是 while you are crossing the road,be careful.的省略,选B的话把cross改为crossing就可以了.
祝开心~!