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：
试题分析:考查不定式做状语：in order to our city green在句中作状语，由于英语中的不定式、介词短语都须有自己的逻辑主语。此句不定式的逻辑主语是we而答案只有D给出了不定式的逻辑主语。（即动词make的发出者或执行者），故此选D
