该患儿发作的机理是A．脱水、血液黏稠 B．脑血栓形成 C．肺动脉漏斗部痉挛 D．感染

I recognized her as soon as I met her at the airport though we hadn't seen each other for ages and she had

changed _____. [ ]

A. a large amount

B. a great many

C. a great deal

D. a great deal of

最适合进行输卵管结扎术的时间是（）

A.正常产后56天

B.正常月经干净后13天

C.难产后72天

D.人工流产后35天

E.月经干净后3～7天

肠结核最好发于

A．回盲部

B．空肠　

C．降结肠

D．升结肠

E．十二指肠

散度的物理意义是（）。