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.  

/ A4 b4 H8 w* g% }' s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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没有接句子
7 \2 t3 i, R3 yit is necessary to have done sth.
接了个完成时的动宾结构
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6 [1 e; V' @( y" X0 g+ s% b你可以对比一下下面两句的含义
) ?' \3 @6 w9 S- H& s" J" Tit's necessary to acquire this.
% B4 v% h) z. [! v) ^有必要（现在或以后）去获取这个
  J, ^6 U1 u) B$ C; \4 V1 U& N, C! dit's necessary to have acquired this.
0 d  a( u; E  x' P0 v( a. t/ W5 R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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