充装易燃、易爆介质的移动式真空绝热低温罐体，其内容器和管路系统内应当进行氮气置换处理，并用氮气密封，露点低于（)℃。
A. -20
B. -25
C. -30
D. -35
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He usually goes out for ___ walk in ___ evening.
A. a, the
B. a, /
C. the, /
D. /, /
His father is ___ old doctor.He often tells him not to smoke in ___ public.
A. a, /
B. an, /
C. an, the
D. /, the
通过留任员工来填补空缺职位的人员规划称为继任计划。（)
动物A有四条腿，B也有四条腿，所以A和B是同一种动物。（)
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