四进制数201（4）表示的十进制数的是[ ]
A．31
B．32
C．33
D．34
答案：C
— Look! The black clouds are gathering, which indicates that it __________ rain soon.
— Yes, black clouds are the _________ of the rain. [ ]
A. is going to; signal
B. will; mark
C. is gong to; sign
D. is to; sign
