请问图里的句子中为什么believed 后需要加介词to？谢谢！

Question

如题所述

Answer 1

to offer protection against a number of cancers. 这里加to. 是一个表达目的的状语。

Answer 2

这个to实际上并不是接在believed后面的，只是在这种句型下碰巧接在了believed后面
to + offer……构成了一个动词不定式，作为believed的补语

改变一下句子的形式，可能更好理解一点
People wildly believe such a diet to offer……

Answer 3

believed原形为believe，believe to 为固定搭配。
望采纳，谢谢！

Answer 4

to不是介词，而是动词不定式的标志符号， 即：
Sb. is believed to do sth.. (to do sth. 是补足语， is belived是谓语动词）
= It is believed that sb. does sth.
= people believed that sb. does sth.
Such a diet is widely believed to offer protection against a number of cancers.
= It is widely believed that such a diet offers protection against a number of cancers.
=People widely believe that such a diet offers protection against a number of cancers.

Answer 5

这是被动，后面的不定式短语作目的状语，不是believed to的搭配。