Every worker has a highly developed sense of how much work______(expect)of him.
第1题:
A. Every 5 minutes
B. Every 90 seconds
C. Every 60 seconds
D. Every 30 seconds
第2题:
第3题:
第4题:
Each life jacket light that has a non-replaceable power source must be replaced ______.
A.every 6 months after initial installation
B.every 12 months after initial installation
C.every 24 months after initial installation
D.on or before the expiration date of the power source
第5题:
第6题: