to 后面可接句子吗？

xixiokok

+ W7 m% Q; }. A2 ~3 B! fIn 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.  
8 O7 R. ]  b: f) q; n: [
这句话里，necessary to 后面为什么可以接 have acquired a ...句子？

江南一屁

; a$ w/ x! {& Q, k6 f4 P$ @% L
没有接句子
it is necessary to have done sth.
2 d' w4 ~/ f1 e* P* k1 ^: ~接了个完成时的动宾结构

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
6 G5 x6 b4 T! O9 ~: s+ Nit's necessary to have acquired this.
! f8 w+ ]& @5 q& X有必要目前已经获取了这个（具有这个是有必要的）