【题目】There is much truth in the ideakindness is usually served by frankness.
A.why
B.which
C.that
D.whether

【答案】C
【解析】句意：这是很有道理的想法,仁慈通常装的坦率。前面有一个名词作为先行词Idea,后面句子成分完整，所以不可能为定语从句，又因为从句的内容就是先行词 idea，所以判断该句为同位语从句，选择C。