—I've been trying to            him for twenty minutes. Why won't he stop crying?

—Ah, Can't you see he is cutting onions? [ ]

A.cheer on

B.cheer up

C.cheered on

D.cheered up

在用电单位的预先约定的计划停电时间，工作人员可以利用该段时间自行进行设备检修。