to 后面可接句子吗？

xixiokok

+ M" Z% ~' c0 o( v0 RIn 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.  

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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9 D+ d4 }4 q& r# H没有接句子
; v  W/ P/ t( w3 ^# z& yit is necessary to have done sth.
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
+ T7 [/ k5 V7 p+ v8 Eit's necessary to acquire this.
9 Q% w$ ~. x, n, C有必要（现在或以后）去获取这个
it's necessary to have acquired this.
& k2 p! F; a( F- Y9 u* i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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