Please because this is a reading room.A. quietB. to be quietC. to quietD. be quiet

问题补充：

Please because this is a reading room.

A. quiet

B. to be quiet

C. to quiet

D. be quiet

答案：

A. quiet

B. to be quiet

C. to quiet

(答案→)D. be quiet

解析：本题是考查祈使句的肯定形式。本题的含义为请保持安静，因为这是阅览室。祈使句使用动词原形开头，表示状态使用动词原形be，be动词后跟形容词quiet，故本题选D。