液压舵机双泵并联工作比单泵工作()。
A.转舵扭矩约提高一倍
B.转舵速度约提高一倍
C.工作油压约提高一倍
D.A和B
参考答案:B
At school, it is essential that every child ______ equally regardless of family background.
A.treating
B.treated
C.be treated
D.is treated
以大城市为中心来考察城市化现象,存在着( )两种类型的城市化。
A.外延和飞地
B.向心与离心
C.景观和职能
D.积极和消极