问题补充:
In order to make our city green, .
A. it is necessary to have planted more trees
B. many more trees need to plant
C. our city needs more trees
D. we must plant more trees
答案:
A. it is necessary to have planted more trees
B. many more trees need to plant
C. our city needs more trees
(答案→)D. we must plant more trees
解析: “使城市绿化”是“我们(we)”的目的。