Cindy shut the door heavily and burst into tears. No one in the office knew she was so an

问题补充：

Cindy shut the door heavily and burst into tears. No one in the office knew she was so angry.

A. where

B. whether

C. that

D. why

答案：

A. where

B. whether

C. that

(答案→)D. why

解析：考查宾语从句。knew后面是宾语从句，从句是主系表结构，不缺成分，句意：辛迪重重的关上了门大哭起来，没有人知道她为什么如此生气。根据句意可知，从句缺少“为什么”这个意思，故用why引导。故选D。