三相异步电动机负载不变而电源电压降低时,其转子转速将()。
A.升高
B.降低
C.不变
D.不一定
参考答案:B
Water Park is a good place _______. [ ]
A. to have fun
B. have fun
C. having fun
D. to have a fun
盐酸小檗碱属于哪类抗菌药
A.喹诺酮类
B.植物成分类
C.酚类
D.磺胺类
E.醇类