37.4

问题描述:

37.4
keep the golden rule in mind ___you never pretend to know when you do not
a.what
b./
c.that
d.b and c

C
同位语从句.因为前面的rule和后面的句子说的是同一个内容,故为同位语.
在同位从语句,不用which,而且that不省略.