液压系统中安全阀的调定值()。
A.低于满载时的工作压力
B.不能超过额定压力
C.低于泵的出口压力
D.不能超过泵的最大压力值
参考答案:D
He was _____at the news and looked at me with his mouth _____.
A.surprised, opened wide
B.amazing, wide open
C.amazing, open wide
D.surprised, open wide
防治稻飞虱的药剂主要有()、锐虱、拂净、飞悬、()。