MSTP设备运行的平均无故障时间（MTBF-Mean Time Between Failure）应不小于（）。
假设VRRP通告消息的间隔设置为2秒，抢占模式为开，Delay Time设置为3秒，则Master故障间隔（Master_Down_Interval）为（）。
中孕期母体血清生化筛查Down氏综合征的最佳时间为（）。
A signal indicating Greenwich mean time would be preceded with（）.
土壤有机质平均停留时间 mean residence time of soil organic matter
The engineer hasn’t got time to track down the problem.‘To track down’ means to find out.
Write down the following time in English in 12-hour clock: 6:20, 12:00.
4-5.What does “Sometimes your whole life boils down to one insane move” mean?
what does stall for time mean?
If a culture has a past-oriented sense of time, what does that mean?
Write down the following time in English in 12-hour clock: 15:50
Write down the following time in English using after/of (the American way):10:23, 3:58
The author of Passage 1 asks the students to remember to regulate and balance their time because too much time online can mean little time in real-life studying or exercising or visiting with friends.
The underlined words “generous with our time” in Paragraph 3 probably mean ______.
Which of the following idioms does NOT mean time flies?
What does “Sometimes your whole life boils down to one insane move” mean?
Write down the following time in English using past / to (the British way): 8:12, 16:43
What does the writer mean by “face time” in Paragraph 37
My mother asked me to repeat ______ telephone number ______ second time so that she could write it down.
It's high time that he settled down in the country and （） a new life.
What does "lead time" in the last paragraph mean？
It's high time that he settled down in the country and start a new life.()
某机器设备在3年内平均停工时间为20h，两次维修之间的平均间隔时间为980h，试求该机器设备的运行可用性
某单位有10部电梯，设电梯工作寿命服从负指数分布，平均工作15天。有一个修理工，修一部电梯的时间服从负指数分布，平均需时2天。求平均发生故障的电梯数及每部电梯平均停工时间。
