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【多选题】
正面吊运起重机动车前必须先（ ）。作业时要在作业区设置（ ）设施，指挥及防护人员应穿（ ），配备口笛或对讲机，站立安全位置。非作业人员及设备不得进入作业区域。
A.
鸣笛提示
B.
了望后动车
C.
安全隔离
D.
反光防护服
参考答案：
参考解析：
刷刷题刷刷变学霸
举一反三
【单选题】医用X射线诊断工作者所受的职业照射，应遵从实践的正当性和防护的最优化原则，任何一年中手、脚的当量剂量不应超过（）mSv。
A.
20
B.
50
C.
150
D.
500
【单选题】According to a survey, which was based on the responses of over 188,000 students, today"s traditional-age college freshmen are "more materialistic and less altruistic (利他主义的 )" than at any time in the...
A.
have never been so materialistic as today
B.
have never been so interested in the arts
C.
have never been so financially well off as today
D.
have never attached so much importance to moral sense