They think important to look right and left when the road.A. it’s; crossB. it; to cross C.

问题补充：

They think important to look right and left when the road.

A. it’s; cross

B. it; to cross

C. it’s;crossing

D. it was; to cross

答案：

A. it’s; cross

B. it; to cross

(答案→)C. it’s;crossing

D. it was; to cross

解析：考查从句知识。句意“他们认为在穿越马路时，往左右看看是重要的。”think后可跟宾语从句，还可以跟宾补结构。第一个空填it’s或it都可；when既可作连词，又可做介词；第二个空可以填they cross或crossing。故选C。