悬浮物的颗粒直径约在（）
A.10-4 mm以上
B.10-6mm以下
C.10-6—10-4mm
D.10-3mm以上
参考答案：A
Jenny went into the room, took off her coat and _____ down on a sofa.[ ]
A. would sit
B. was sitting
C. sat
D. had sat
雨淋阀的自动控制方法有（）。
A、湿式控制系统
B、干式控制系统
C、电气控制系统
D、易熔金属拉锁
