经营杠杆作用是以成本中存在（）为基础的。
A.固定成本
B.变动成本
C.固定负债
D.固定利息
参考答案：A
—I am sorry．I broke your mirror． —Oh，really? ．
A．It’s OK with me
B．It doesn’t matter
C．Don’t be worry
D．I don’t care
－What are you going to be when you grow up?
－I’m going to be _____ English teacher in ______ university.
A．a, the
B．an, an
C．an, a
D．the, an
