进攻基础配合是组成全队进攻战术的（）
A.内容
B.基础
C.条件
D.方法
参考答案：B
---- Do you like her friends?
---- Yes. One of her friends often _______ her _____ her English in the class.
A．help, with
B．help, to do
C．helps, doing
D．helps, with
三相异步电动机在空载运行时，其转差率( )
A．S≈0
B．S≈0.5
C．S≈0.99
D．S≈1
