notice 不是感官动词吗?为什么这句话重用的是to be 而不是be,难道是this的定语?

notice 不是感官动词吗?为什么这句话重用的是to be 而不是be,难道是this的定语?
补充感官动词只接do（原形）We notice this to be true very often with dogs and cats
这是书上的一句话！
Do Animals
Think?
The question has
often been asked,Do animals think?I believe that some of them think a great
deal.Many of them are like children in their sports.We notice this to be true
very often with dogs and cats; but it is true with other animals as
well.
Some birds are very lively in
their sports; and the same is true with some insects.The ants,hardworking as
true of the owl,who always looks as if he were considering some importa.加我百度账号！书上的翻译是，我们注意到 这一点就狗和猫而言是对的。我个人还是认为to be true 是this 的定语 比如上句只是给出了一个范围 many animal s但是并没有强调是猫和狗，而to be with 作为限定定语，恰好强调了 关于猫狗是对的而其他的另说，下一句用but恰好又表达了对比的，强调一个事实的用法对于其他动物也一样。整个 we notice 是为了论证前面一句话的的论证部分。