Question

The reason______ he gave for being absent from school was __

Answer 1

C

先行词为表原因的the reason, 且从句中的gave缺宾语, 所以第一空用关系代词that 或which用作gave的宾语, that 或which可以省略; 第二空是由that引导的表语从句, 即The reason …is/ was that…句式。