在下面列出的数据模型中,哪一个模型是概念数据模型A.关系模型 B.层次模型 C.网状

题型:单项选择题

问题:

在下面列出的数据模型中,哪一个模型是概念数据模型

A.关系模型

B.层次模型

C.网状模型

D.实体—联系模型

考点:计算机等级考试数据库技术三级数据库技术笔试
题型:单项选择题
Blood donation, also called blood banking, is a wonderful thing to do. It is an easy and direct way to contribute to social work and help the community. It helps to save lives and helps those who are in need of blood due to bad condition or the heavy loss of blood during operations or in accidents.
You are able to give or donate blood every three or four month, and it is a great way to make  a huge difference to someone’s life and you can always be proud of it after making valuable contributions to society. Blood donation is not a big problem, but you need to keep a few points in mind.
Before donating blood, make sure that the ferrum (铁) level in your body is high enough and for that you should take a healthy diet. Do not go for blood donation on an empty stomach. You should follow the correct process so that everything goes well. After having a balanced diet you will feel strong and comfortable to donate blood. Afterwards, you will not feel faint or weak.
For required hemoglobin (血红蛋白) in your body, drink lots of juice and other drinks. Fruit juice, such as apple juice is very good for increasing the blood level in your body.
For a good blood flow in your body, drink at least 6-7 glasses of water every day. Completely avoid a day before and after giving blood, taking alcohol (酒). Do not smoke half an hour before giving blood.
When you are going for blood donation, be relaxed, which helps keep the right blood pressure. During the blood donation activity, take a deep breath and try to calm yourself. Don’t join in some other activities.
When you donate blood, you are making the effort to save someone’s life. Blood donation is a very simple and fast process, but you need to take care of yourself after donating blood. Proper care helps to reduce side effects. The following are a few tips that will help you out.
Take a rest for 15 minutes after the donation. It helps you to feel relaxed.
Eat something and drink juice before leaving the blood donation centre. Make sure that you have meals after donating blood. Smoking should be avoided for one hour after the process. Avoid some activities right away, for example, driving.
Finally, be proud of yourself because you have done a great thing in helping to save someone’s life. Blood donation is a very important activity.
Title
Blood donation — an important activity
The (1)      of blood donation
? (2)      to social work and the community
? Helping those people who suffer the
loss of (3)     
? Giving yourself a sense of pride
(4)      the donation
? Take a healthy (5)      for a high ferrum level.
? Drink fruit juice for enough hemoglobin.
? Drink at least 6-7 glasses of water daily for a good (6)      of blood.
? (7)    taking alcohol and smoking cigarettes.
During the donation
? Relax and breathe deeply
? Never take (8)      in other activities.
After the donation
? Take a rest.
? Don’t skip (9)     .
? Don’t smoke until one hour later.
? Don’t join in some activities like driving
(10)     
题型:单项选择题

关于染色体、DNA、基因的关系叙述不正确的是

A.染色体上有DNA,DNA上有基因

B.人的体细胞中有23对染色体,每条染色体的物质组成主要是DNA和脂肪

C.DNA是染色体的组成成分,基因是DNA分子的片段

D. DNA是遗传信息的载体

题型:单项选择题

张某有一笔闲置资金欲进行投资,要求收益稳定,风险小,则其最佳投资方式为( )。

A.购买固定资产投资

B.购买已上市普通股股票投资

C.购买优先股股票投资

D.购买上市债券投资

题型:单项选择题

史料记载:1876年,中国宁波海关税务司李圭首次参加在美国举办的世界博览会,他发现美国展品“约居十之八”,而中国“竞无一物于此”。会后,他大声疾呼“机器正当讲求”(意思是中国迫切需要采用西方的先进生产技术)。他喊出了下列哪个派别的心声[ ]

A.顽固派     

B.洋务派     

C.维新派     

D.资产阶级革命派

题型:单项选择题

制作松花蛋常用到熟石灰和纯碱等原料,食用时常有涩味。可在食用前添加调味品,这种调味品最好是    [ ]

A.酱油    

B.食盐    

C.香油    

D.食醋

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