A. 振荡器 B. 放大器 C. 单稳态触发器 D. 双稳态触发器
A. stretches too much B. is too difficult to make fast C. parts too readily D. is too susceptible to mildew
A. 容易受潮 B. 容易吸尘 C. 容易挥发
A. 正确 B. 错误
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