to 后面可接句子吗？

xixiokok

In 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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: S4 V& q! I, w6 P$ o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

没有接句子
it is necessary to have done sth.
+ F) z' i0 m/ M接了个完成时的动宾结构

  g6 `4 b3 Z+ Y' I$ Y& |你可以对比一下下面两句的含义
it's necessary to acquire this.
1 l+ L* Q, P3 d$ \* f# U有必要（现在或以后）去获取这个
+ S6 `% |0 D6 pit'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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