外科感染的发生，最重要的原因为 A．伤口的存在 B．致病菌入侵人体 C．局部组织血

分别用一句话介绍四个季节。

1. Winter____________________________________.

2. Spring____________________________________.

3. Summer__________________________________.

4. Fall______________________________________.

下列哪几种疾病能引起肠道狭窄（）

A.肠阿米巴病

B.肠伤寒

C.细菌性痢疾

D.肠结核

The project team is working on an important and complex project that requires a lot of coordination．Under these circumstances，the BEST strategy is to______．

A．have a war room

B．hire a contractor

C．hold more meetings to get the word out

D．gain extra assistance from management

抗病毒感染中起局部免疫作用的抗体是（）.

A.IgG

B.IgM

C.IgA

D.SIgA

E.IgE

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