谁能帮我解释一下这几道定语从句题?

题目

谁能帮我解释一下这几道定语从句题?
这些道题选哪一个?为什么?
70.Do you understand the theory ______
A.that how the living things came into being
B.how did the living things come into being
C.of how the living things come into being
D.of how did the living things come into being
77.All of the plants now raised on farms have been developed from the plants _____ wild.
A.once they grew
B.they grew once
C.that once grew
D.once grew
3.Don’t trust such men _____ praise you to your face.
A.as B.who C.that D.which

答案

70.A:同位语从句以that引导 后面的从句是theory的同位语77.C:定语从句以关系词引导,此处在从句中作主语,所以关系词不能省略.所以选择C3.A.as引导的定语从句常与such...,the same...连用：但要注意,such...that...：...