（）是指必须经过两次以上拍卖程序才拍定的拍卖。
A.有保留价拍卖
B.一次性拍卖
C.再拍卖
D.无保留价拍卖
参考答案：C
-They are thirsty. Will you please give them _____?
-Certainly.[ ]
A. some bottle of orange
B. some bottles of oranges
C. some bottle of oranges
D. some bottles of orange
GPS接收器的工作电压是（）。
A.5V
B.12V
C.6V
D.24V
