Students need at least eight hours to sleep or they are in class.A. sleepB. sleepyC. asl

问题补充：

Students need at least eight hours to sleep, or they are in class.

A. sleep

B. sleepy

C. asleep

D. sleeping

答案：

A. sleep

(答案→)B. sleepy

C. asleep

D. sleeping

解析：根据前一句Students need at least eight hours to sleep，再加上or表示否则的意思，故选答案为B，表示困倦的，符合题意。