— Excuse me, sir. Would you please             the total cost of the trip?

— All right, I will make it at once.

A．give out

B．look out

C．take out

D．work out

8250除数寄存器的值用于确定通信波特率，它必须在8250初始化时预置，为此，应先把通信线控制寄存器的______位(DLAB) 置为1，然后将其分别写入高8位除数寄存器和低8位除数寄存器。