对不间断交流电源来说,当失去相关的380V电源时,将出现什么情况?该母线电压是否受影响?为什么?
参考答案:
将由蓄电池供电,母线电压不变,蓄电池为备用电源。
By using MP3, a 600M-byte music CD can be (70) to 50M bytes or less. It can be streamed (downloaded in chunks)so that you can begin listening to the opening bars while the (71) of the file arrives in the background. And, most important, MP3 music files retain good listening (72) that (73) compression schemes lacked. That (74) of features makes accessing and distributing music on the Web practical for the first time.
A.earlier
B.front
C.backward
D.later
以公开招标方式选择咨询公司的具体步骤的第一项是( )。
A.准备短名单
B.发邀请函
C.估算咨询费用
D.编制工作大纲