1．In the past, the respect for teachers was driven by the belief ________ they were reliable sources of knowledge.
A．which B．what
C．that D．when
答案与解析：C 根据句子结构可知，后面的从句是对belief的内容进行说明的，作其同位语，从句中不缺少成分，故用that引导。
2．The scientists haven't found the evidence ________ human beings came from the space.
A．which B．that
C．what D．who
答案与解析：B that在本句中引导同位语从句，说明evidence的具体内容。句意：科学家们还没有发现人类来自太空的证据。
