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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0 c4 P4 ~7 b6 s! c4 y  C这句话里，necessary to 后面为什么可以接 have acquired a ...句子？

江南一屁

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0 W3 N7 A- S0 q2 @- A没有接句子
: R# t5 |6 J1 kit is necessary to have done sth.
8 M2 `. T4 x) P% \接了个完成时的动宾结构
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你可以对比一下下面两句的含义
& d5 i* ~  L7 Z# ]# Xit's necessary to acquire this.
- W! X" L/ j4 j# v' h- q3 I  z有必要（现在或以后）去获取这个
it's necessary to have acquired this.
$ L8 E) o# D' \6 Q5 M2 a" ]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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