【简答题】(16分)(Ⅰ)下列实验操作或实验叙述正确的是( ) A.可用过滤的方法除去氢氧化铁胶体中少量的氯化铁 B.用酸式滴定管量取18.80mL的碳酸钠溶液 C.配制0.1mol/L的硫酸时,用量筒量取浓硫酸,要洗涤量筒,否则配制的溶液浓度偏低 D.振荡用饱和的碳酸钠溶液吸收乙酸乙酯的试管,发现有气泡冒出,它是CO 2 气体 E.实验室制取氨气时,常用无水氯化钙进行干燥 (Ⅱ)红矾钠(重铬酸钠:Na...
【单选题】Pilots should contact _________ or their departure airport control tower if they need to change their departure time.
B.
the departure controller
【判断题】维生素K是一类具有凝血作用、含有甲萘醌结构特点的维生素
【单选题】汉译英:“原产地;有效期限”,正确的翻译为( )。
A.
place of issue Departure time
B.
place of origin Departure time
C.
place of issue Valid period
D.
place of origin Valid period
【单选题】The insurance shall be ()from the time of the engineer’s departure from China up to the time of his arrival in China on return.