--Be quiet! The children now.Oh sorry. A. sleepB. sleptC. were sleepingD. are sleepin

问题补充：

--Be quiet! The children now.

--Oh, sorry.

A. sleep

B. slept

C. were sleeping

D. are sleeping

答案：

A. sleep

B. slept

C. were sleeping

(答案→)D. are sleeping

解析：从时间状语now现在，可知此句为现在进行时态，children为复数形式，be动词用are，所以选D。