According to the passage, which of the following statement is not true？
A. the heat exchanging surfaces should be kept substantially clean
B. the heat exchanger flow passages should be clear of obstruction
C. seals for the plate heat exchanger needs to be renewed often
D. the cleaning process of the plate heat exchanger should be done following our experiences only
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The depth of the ship below the waterline measured vertically to the lowest part of the hull is called
A. trim
B. lean
C. draft
D. tonnage
_______应与活塞中心线垂直相交，垂直度要求不大于0.025mm/100mm，位置度要求：活塞直径＜200mm时应不大于0.10mm；活塞直径＞200mm时应不大于0.20mm
A. 环槽平面
B. 活塞销孔中心线
C. 曲轴中心线
D. 活塞顶面
下面哪一项不会使总需求曲线移动？________。
A. 对未来的预期
B. 货币工资率
C. 财政和货币政策
D. 外国收入
E. 外汇汇率
下面哪一项会使总需求曲线向左移动？________。
A. 政府在产品和服务上支出的减少
B. 价格水平的上升
C. 税收减少
D. 外国收入增加
E. 价格水平下降
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