员工尽量使用（），纸杯是给来客准备的。
A.一次性塑料杯
B.自己带的纸杯
C.自己的水杯
参考答案：C
—I don’t know makes her different from others.
—Confidence, I think.
A．how is it that
B．how it is that
C．what is it that
D．what it is that
ISO模型分为几层（）；
A、5
B、6
C、7
D、8
