应急照明备用电源应能保证应急照明控制器正常工作()。
A.1h
B.2h
C.3h
D.5h
参考答案:B
In the past,ice ______food.
A.used to keep
B.used to be used for keeping
C.was used to keeping
D.used to be used to keeping
特快专递邮件是以()速度传递处理的邮件。
A.一般
B.最快
C.较快
D.快