Don’t talk here. Grandparents .A. sleepB. is sleepingC. are sleepingD. sleeping

问题补充：

Don’t talk here. Grandparents .

A. sleep

B. is sleeping

C. are sleeping

D. sleeping

答案：

A. sleep

B. is sleeping

(答案→)C. are sleeping

D. sleeping

解析：此处需用现在进行时：be＋现在分词，因为主语是第三人称复数，故选C