“走息道以行呼吸，贯心脉以行气血”的气是（）。
A.胃气
B.宗气
C.营气
D.卫气
E.元气
参考答案：B
The little boy ________ in the mud all the morning. No wonder he is dirty from head to foot.[ ]
A．has played
B．is playing
C．has been playing
D．was playing
（）通常为深灰色或钢灰色。
