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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& a" \5 M: B1 H5 a8 e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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it is necessary to have done sth.
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你可以对比一下下面两句的含义
it's necessary to acquire this.
# ~! @  l9 y8 K, M  _有必要（现在或以后）去获取这个
0 W7 V/ ?4 W+ s7 g' eit's necessary to have acquired this.
- B1 n' H7 ~4 q! u/ z. [0 L+ j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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