矿井安全监控装置中,测量低浓的甲烷传感器主要是()催化元件。
A、铂丝
B、载体
C、电化学
参考答案:B
The little girl always the windows in class. This her teacher very angry(生气的)
A.looks out, makes
B.looks out at,making
C.looks out of,makes
D.looks like,make
在出口业务中,如果国外客户已下订单,不管是否已经收到信用证,为防止货价上涨,出口商必须提前备货。 ( )