氟的防龋机制不包括A.釉质溶解性增加 B.抑制烯醇酶 C.促进再矿化 D.抑制细菌产

题型:单项选择题

问题:

氟的防龋机制不包括

A.釉质溶解性增加

B.抑制烯醇酶

C.促进再矿化

D.抑制细菌产酸

E.影响牙外形

考点:口腔执业医师口腔执业医师70
题型:单项选择题

阅读理解。

     Before you to another country it is a great help if you know the language and some of the customs

(风俗) of the country.

     When people meet each other for the first time in Britain, they say "How do you do?" and shake

hands(捏手). Usually they do not shake hands when they just meet or say goodbye. But they shake

hands when they haven't met for a long time or when they will be away from each other for a long time.

      Last year a group of German students went to England for a holiday. Their teacher told them that

the English people hardly ever shake hands. So when they met their English friends at the station,  they

kept their hands behind their backs. The English students had learned that the Germans shake hands as

often as possible, so they put their hands in front and got ready to shake hands with them. It made both

of them laugh.

根据短文内容,选择正确答案。  

1.It is      _ if you know the language and some of the customs of a country before you pay a visit to that country.        

A. not useful                

B. not helpful

C. very helpful              

D. very bad    

2. English people usually shake hands when they     __.      

A. meet every time

B. meet for the first time

C. say goodbye to each other

D. say hello to each other    

3. Usually, English people don't shake hands       __.        

A. when they will be away for a long time

B. when they say "How do you do?"

C. when they just meet or say  goodbye

D. when they haven't met for a long time  

4. Which is RIGHT?       

A. German people shake hands as often as possible.

B. English people like shaking hands very much.

C. German people hardly ever shake hands.

D. Both English people and Germans don't like shaking hands.

5. This story is about__      .

A. shaking hands

B. languages

C. customs

D. languages and customs

题型:单项选择题

有关AIDS典型艾滋病期的描述,错误的是()。

A.播散性分枝杆菌感染少见

B.出现各种致命性机会感染

C.出现各种恶性肿瘤,如卡波西肉瘤等

D.卡氏肺囊虫肺炎多见

E.预后极差

题型:单项选择题

重症肌无力常可以合并以下哪些自身免疫性疾病()

A.甲状腺功能亢进

B.甲状腺炎

C.系统性红斑狼疮

D.类风湿关节炎

E.天疱疮

题型:单项选择题

直角刚杆AO=2m,BO=3m,已知某瞬时A点的速度vA=6m/s,而B点的加速度与BO成β=60°角,则该瞬时刚杆的角加速度α为()rad/s2

A.A

B.B

C.C

D.D

题型:单项选择题

石灰土基层中,粉碎土块的最大尺寸不应大于()。

A.5mm

B.10mm

C.15mm

D.20mm

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