Timmy said to _____, " I'm trapped ". [ ]
A. me
B. myself
C. his
D. himself
答案:D
校验双法兰液位变送器时,其两个法兰点应()。
A.保持一定高度
B.放在同一平面上
C.随意放置
锋面是:()
A.高压与低压交界
B.干湿气团交界
C.冷暖气团交界
D.大气与下垫面交界