背压回路以形成一定的回路阻力,用以产生背压,一般背压为( )MPa。
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下片作者描写的是梧桐夜雨,其实反映出女子彻夜难眠。()
A. 对
B. 错
Low prices can drive competition 1______________.Dumping is considered a 2________________ pricing practice.The 3______________ involves adding a certain percentage.The company is being sued because it was pricing 4_________________.
环式力传感器与柱式相比,其特点是应力分布变化大,且有正有负,便于接成差动电桥。
A. 对
B. 错