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.  

# o0 y; x' {8 \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

+ P- ^! L, y9 C+ p) c3 n没有接句子
it is necessary to have done sth.
9 j9 J6 y# M! |! e$ R& I接了个完成时的动宾结构

& Z0 }" X* J& J: c你可以对比一下下面两句的含义
it's necessary to acquire this.
有必要（现在或以后）去获取这个
- ~; J8 @5 n1 Q' a3 Y0 ^: uit'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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