哪种仪器不属于压力计。（）
A、膜合式压力计
B、弹簧管压力计
C、U形管压力计
D、孔板流量计
参考答案：B
A best friend is one who can always read your minds when you are at a loss for the ________ words
to complete your thoughts.[ ]
A. temporary
B. absolute
C. precise
D. reliable
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