题目

After her husband was put into _____prison, she had to make _____living by selling flowers. A . a; a B . /; a C . /; the D . a; the 答案：B20．在2A+B?3C+4D反应中，表示该反应速率最快的是（　　）A．VA═0.5mol L-1S-1B．VB═0.3mol L-1S-1C．VC═4.8mol L-1min-1D．VD═1mol L-1S-1