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【单选题】
The selection of spare spring in suction valve and delivery valve of first stage must bevery careful because_____.A.
the spring assembly design is very critical to ensure correct valve action
B.
it is usual for the suction valve to have a lower spring pressure than the delivery valve
C.
the valve operates once every revolution and the valve movements are extremely frequent
D.
if the compressor is overheating wear and fatigue will occur
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【简答题】A．He hates modem art. B．He wants to understand the art. C．He doesn't like psychology. D．He doesn't want to hear any explanations.
【简答题】用经济活动的基本和非基本理论解释城市的发展。
【单选题】---Do they like music or art? ---_______.
A.
Yes, they do
B.
No, they don't
C.
Yes,I think they like art
D.
They like art
【单选题】下列礼盒套装,可以按照协调制度归类总规则中所规定的“零售的成套货品”进行归类的是:
A.
内有咖啡一瓶、咖啡伴侣一瓶、银制杯子一只
B.
内有一瓶白兰地酒、一只打火机
C.
内有一包巧克力、一个塑料玩具
D.
内有一支红酒、一个红酒启瓶器
【单选题】以下说法不正确的是
A.
糖衣有一定防潮，隔绝空气的作用，并可迅速溶解，对片剂崩解影响不大
B.
薄膜衣片剂比糖衣片生产周期短，效率高
C.
半薄膜衣是薄膜衣和糖衣的结合，包时先包2～3层薄膜衣，再包裹几层粉衣层和糖衣层
D.
AP包衣后的片剂能溶解于pH5．8～6．0的缓冲液中
E.
目前常用色素有水溶性，水不溶性，色淀等三类
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