You are on a containership carrying a tank container that had been filled with sodium hydroxide solution. The container is empty but has not been cleaned. Which，if any，placard is required?（）.
A. No placard is required; the tank openings must be sealed
B. Empty placard with corrosive placard
C. Residue label with the UN number
D. Black and white corrosive placard
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拟态（mimicry）的含意是：（）
A. 昆虫身体表面的微型感觉毛
B. 某些种类的昆虫通过模拟其他种类的昆虫而得到特殊的保护
C. 在预示着危险的外界刺激的影响下某些昆虫所处的状态
D. 一些昆虫雌虫的行为，此行为意在吸引雄虫
屈子祠位于湖南省泪罗，是为纪念屈原而于唐代建祠。
A. 正确
B. 错误
A diesel engine cooling water system with a pH factor of 30 indicates a condition of （）.
A. slight acidity
B. slight alkalinity
C. excessive alkalinity
D. excessive acidity
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