When you go the street you must be careful.A. crossingB. crossC. acrossD. pass

问题补充：

When you go the street, you must be careful.

A. crossing

B. cross

C. across

D. pass

答案：

A. crossing

B. cross

(答案→)C. across

D. pass

解析：句意：当你过马路是，一定要小心。Cross 穿过，动词，句中已有动词做谓语，不合题意。Across穿过，介词，符合题意。Go across穿过，故选C。pass通过，动词。