下面选取项中,()信号不会引起给煤机跳闸。
A.FCB
B.MFT
C.磨煤机跳闸
D.给煤机皮带上无煤
参考答案:D
The old man has devoted half his life _____ helping the weak. [ ]
A. of
B. to
C. by
D. for
支配骨骼肌的躯体运动神经释放的递质为()
A.肾上腺素
B.去甲肾上腺素
C.儿茶酚胺
D.多巴胺
E.乙酰胆碱