题目内容：

If you want to walk 横线the street,you must look left first then right before 横线it
A.across; acrossing B.cross,across
C.across;crossing B.cross;crossing

优质解答

C
walk across the street 过马路,动词walk 后用介词 across
before crossing it ,before 是介词,后面跟动词ing 形式.

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