给水泵严重汽化的现象,入口管和泵内发生不正常的();给水泵出口压力()。
参考答案:噪音;摆动和降低
The population of many Alaskan cities has ______ doubled in the past three years.
A.as great as
B.as many as
C. more than
D.larger than
UM71轨道电路用0.15Ω标准分路电阻线分路,死区段长度不应大于()m。