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【单选题】
下列关于离心泵描述错误的是A.
离心泵主要结构由叶轮、泵壳、泵轴及轴封装置
B.
按结构叶轮可分为弯叶、平直叶和折叶
C.
离心泵泵壳为蜗壳型,其作用是汇集液体和能量转换
D.
离心泵的泵轴与泵壳之间的轴封分为填料密封和机械密封
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皮皮学刷刷变学霸
举一反三
【简答题】土的颗粒密度和土粒比重从数值上讲二者是()的。
【简答题】土的颗粒密度和土粒比重从数值上讲二者是()的。
【单选题】There’s still much uncertainty about what it is like to study online. In the sentence, “uncertainty” means:
A.
suspect
B.
guess
C.
doubt
D.
worry
【单选题】Passage 2--- 4. What is the speaker’s attitude toward uncertainty and settling down?
A.
It is better to settle down later.
B.
It is better to settle down earlier.
C.
It is necessary to try every means to avoid uncertainty.
D.
It is not necessary for people to avoid uncertainty.