人体生命活动的原动力是（）。
A．宗气
B．营气
C．元气
D．卫气
E．中气
参考答案：C
The robot needs _____. You'd better _____. [ ]
A. repaired; have it repair
B. to be repaired; have it repaired
C. repairing; have it to repair
D. to be repaired; have it repairing
B超检查正常成人肝脏组织的回声表现是（）
A.均匀
B.粗糙
C.低回声
D.不均匀
E.强回声
