当维护机电设备安全的()因紧急情况工作时,应发出声光报警装置。
参考答案:安全系统
The engineers are so busy that they have no time for outdoor sports activities,________ they have the interest.
A.wherever
B.whenever
C.even if
D.as if
RIP的最大跳数是( ):
A.24
B.18
C.15
D.12