下列精炼方法不具备真空的是（）。
A．AOD
B．VOD
C．RH-OB
D．VD
参考答案：A
The teacher demanded all the exercise books ______ the next day.
A．to be handed in
B．would be handed in
C．be handed in
D．to hand in
32. It is certain that he will _____ his business to his son when he gets old.
A．take over
B．give away
C．hand over
D．wrestle with
away