to 后面可接句子吗？

xixiokok

% g( M9 M6 T# u* K, J) L, W2 q, IIn order to design policies that aim to change commuting practices it is, however,necessary to have acquired a good understanding of the trips in question and their determinants.  
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这句话里，necessary to 后面为什么可以接 have acquired a ...句子？
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江南一屁

9 S+ o. T, b. d# Y) ?5 X没有接句子
it is necessary to have done sth.
接了个完成时的动宾结构

+ s& a1 q0 ], T. D) y% O1 K: z你可以对比一下下面两句的含义
it's necessary to acquire this.
2 V9 w7 [! t1 `有必要（现在或以后）去获取这个
6 [: ~- B' \' z* c- r* ^it's necessary to have acquired this.
有必要目前已经获取了这个（具有这个是有必要的）


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