下列各项中，具有“走息道以行呼吸，贯心脉以行气血”功能的气是（）
A.元气
B.宗气
C.营气
D.卫气
E.胃气
参考答案：B
同学们乘船参加夏令营活动，全部住四等舱；四等舱有15个房间，每间12个床位．住满了13个房间后，还剩5人，共有多少人参加夏令营活动？
It's great fun to go hiking in the valley, but______, we shouldn't turn a blind eye to the potential risks. [ ]
A. on the other hand
B. on the contrary
C. as a matter of fact
D. as a result
