活动力极强、流动很迅速的气是（）
A.卫气
B.清气
C.元气
D.宗气
E.营气
参考答案：A
Are you paying now, or shall I ＿＿＿＿＿＿ to you?
A．book it down
B．book it in
C．book it up
D．book it out
布白与留空
