Mary has a bad cold. She has to stay in bed.A. a B. theC. /

问题补充：

Mary has a bad cold. She has to stay in bed.

A. a B. theC. /

答案：

解析：

试题分析: 句意：玛丽感冒了，她不得不呆在床上。In bed在床上，固定词组，不加冠词，故选C。