被测电路电压不能超过钳形表上所标明的数值，否则容易造成（）。
A.接地事故
B.引起触电危险
C.短路
D.损坏钳形表
参考答案：A, B
I often have _______ egg and a glass of milk for _______ breakfast every day.
A．an; /
B．a; /
C．an; the
D．a; the
