医院内尿路感染的常见诱因是()
A.留置导尿管
B.气管切开
C.两者均是
D.两者均否
参考答案:A
There are many __________ shops in this street. I want a pair of ________ shoes.
A.shoe, sport
B.shoes, sport
C.shoe, sports
D.shoes, sports
试述网络咨询的主要形式。