侵袭性操作的高危因素()
A.留置导尿管
B.静脉导管
C.气管插管
D.器官移植
E.吸取痰液
参考答案：A, B, C, D, E
About seventy percent of the earth with water.
A．is covering
B．is covered
C．are covering
D．are covered
什么是市政？什么是市政管理学？
