以下因素影响龈下菌斑的细菌组成，除外（） A.龈沟和牙周袋的解剖条件 B.龈沟内

根据短文内容，选择正确选项。

     Cerms(细菌)are everywhere. You can't see them, but they are on your desk,on your computer,and

even in the air!   

     Like people, germs move around the world. They fly with us on planes.When food , clothes,and other

things travel around the world,germs travel , too. Some germs are safe , but some are dangerous. Germs

cause illnesses like colds and the flu.    

     Warmer Weather Brings Germs    

     The world's weather is changing. Cooler countries are getting warmer, so insects from hot countries can move there. Some of these insects, like mosquitoes,carry dangerous germs. Tlhese germs cause

headaches,fevers, and can even kill people.   

     Under Your Skin    

     Your skin protects you from germs.It stops some germs,but not all.They can enter your  body when

you eat,or when you have a cut. Germs are on your hands,too.They enter your body when your touch your eyes,nose, or mouth.    

     Fighting Germs    

     Your immune system (免疫系统)protects you,too. When germs get inside your body, your immune

system finds and kills them. Special cells(细胞)move around your body and fight germs.They help you stay healthy. Other cells make antibodies.Antibodies help your body find and stop germs.    

     What can you do to fight germs?You should wash your hands with soap and water. Soap kills many

germs,and water washes them away.

1. According to the text,insects         .    

    A. kill germs

    B. carry germs  

    C. protect germs

    D. love germs

2. The underlined word"there"refers to            .    

    A. cooler countries    

    B. hot countries    

    C. everywhere    

    D. the world

3. Which of the following is RIGHT according to the text?   

    A. All germs are dangerous.    

    B. There are more germs in cold places.    

    C. Soap can kill all germs.  

    D. Germs can get into your body.

4. What do antibodies do?   

    A. They kill germs and wash them away.   

    B. They find and develop germs.    

    C.They help protect us from germs.   

    D. They carry dangerous germs.

5. Which can be the best title for this text?   

    A. Germs Are Everywhere   

    B. Weather Is Changing    

    C.Skin Stops Germs    

    D.Germs Are Developed

患者，男性，45岁，双下肢棕褐色斑疹，无明显自觉症状。查体发现皮损位于胫前区，皮损周围散在针尖大小的瘀点。最可能的诊断是（）

A.单纯性紫癜

B.进行性色素性紫癜性皮病

C.色素性紫癜性苔藓样皮炎

D.淤积性皮炎

E.过敏性紫癜

下列各对物质中，互为同系物的是 

A．CH₃-CH=CH₂与

B．

C．甲苯和二甲苯

D．

远洋船舶保险定期保险的保险期限最短为()。

A.1个月

B.2个月

C.3个月

D.4个月

石油的组成及各种成分的主要物质有哪些？