to 后面可接句子吗？

xixiokok

* z5 B) a4 x# |  j) Z7 g! lIn 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

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) M( e. |4 q; F5 M1 K! {没有接句子
3 ~5 F( A) }& `5 S2 Q6 ^6 ?# Wit is necessary to have done sth.
3 U. y1 Q7 X/ Y接了个完成时的动宾结构

6 X: P' J9 X2 r* J, I你可以对比一下下面两句的含义
it's necessary to acquire this.
8 L/ }2 d& x: G9 l有必要（现在或以后）去获取这个
8 W, Q0 N0 S8 f* y% o& wit's necessary to have acquired this.
, G8 U! g6 e& K: C) p! o" U, _有必要目前已经获取了这个（具有这个是有必要的）