计价员计价时可使用的笔为
A.黑色钢笔
B.蓝色钢笔
C.红色钢笔
D.黑色铅笔
E.蓝色圆珠笔
参考答案:A,B,E
—"I stayed at a hotel while in New York."
—"Oh, did you? You _____ with Barbara."
A.could have stayed
B.could stay
C.would stay
D.must have stayed
某量程为0~10MPa的计量仪表,其允许最大误差为0.05MPa,则其精度等级是()。
A、0.5
B、0.05
C、0.005
D、0.0005