卸储煤设备多采用开式齿轮传动,齿轮失效的主要原因是()。
A.齿面磨损
B.应力集中
C.疲劳点蚀
D.胶合
参考答案:A
____ the risk of a shark attack, you should follow these suggestions.
A.Reduced
B.To reduce
C.To reducing
D.Reduce