Question

On the third floor there are two rooms, ________ is used as a meeting-room．

Answer 1

答案B
由于空前有逗号，A项不能表明前后两句的关系，可排除；从句意看出，提到了三楼的两个房间，所以最高级的D项可排除；由于应选的答案在后面的句子中作主语，所以比较级前应用定冠词，用B项引导定语从句。