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更多“The advancement of eco-tourism…”相关的问题
1、兼职工作
2、劳动市场
3、升职机会
4、工作前景
5、职业道路
6、专业经验
7、采取步骤
8、自我分析
9、设定目标
10、行为计划
A、job outlook
B、self analysis
C、take steps
D、part time job
E、action plan
F、advancement opportunity
G、career path
H、professional experience
I、labor market
J、set goals
请将两组内容相关的项连起来
For most people,learning a foreign language does not come easy,for it requires hard work and consistency. ____1 and foremost,there must be some motivations for learning a language.Are you planning to head to a foreign destination？ Is learning a language on your wish list？ Is it important for job advancement？ ____2 any measure,the critical success factor is how much time you are taking to involve yourself ___3 the language.The more time you dedicate ____4 the language,the quicker you will learn.So,what does spending time really mean？ It means listening,reading,writing,speaking,and studying words and phrases at every available opportunity.Involve as many senses _____5 possible in the learning process.
We could start with the advantages of mobile phones. There are many things that we could do with mobile phones. With the advancement of technology，more and more features are being added to the mobile phones which make them more useful. In addition to making calls，mobile phones also support a wide variety of other services such as text messaging，email，Internet access，business applications，gaming and photography. We can bring them everywhere，and can be reached by others anytime. They make the world smaller，bringing people together no matter where they are.
But we could have some risks when using our mobile phones. We may have accidents when we use them while driving. Some studies show that mobile phones can do harm to our bodies;and materials in mobile phones could damage our environment.
Since there are so many risks，why do we still have mobile phones？This is because these risks or disadvantages can be overcome. For example，while we are driving we can easily pull up our car if we really need to use the phone. Mobile phone manufacturers are reducing the radiation of mobile phones to avoid health risks.
Though there are both pros and cons of using mobile phones，we could easily see that there are more advantages than disadvantages. Moreover，mobile phones are becoming cheaper，which might be another reason why mobile phones are increasingly used today.
1. Which of the following functions is NOT mentioned in the passage？
A. Text messaging.
B. Camera.
C. GPS.
2. What risks might mobile phones cause？
A. Traffic accidents and health problems.
B. Environmental damage.
C. Both A and B.
3. What are mobile phone manufacturers doing to prevent mobile phone users from health risks？
A. They are reducing the radiation of mobile phones.
B. They are trying to persuade people to use mobile phones less.
C. They are developing new models of mobile phones.
4. Why do people still use mobile phones despite their disadvantages？
A. Because people don’t believe that mobile phones have any disadvantages.
B. Because the disadvantages of mobile phones can be avoided.
C. Because people cannot live without mobile phones.
5. According to the last paragraph，why are mobile phones increasingly being used today？
A. They are safer.
B. They have more functions.
C. They are becoming cheaper.
设随机变量X的分布律为
求E(X)，E(x2)，E(2X+3).
设随机变量ξ的分布列为
求E(ξ),E(-ξ+1),E(ξ2).
A.CF(H，E)=0
B.CF(H，E)＞0
C.CF(H，E)＜0
D.CF(H，E)=-1
A.设c是常数，则有E(C)=C
B.设X是一个随机变量，C是常数，则有E(CX)=CE(X)
C.设X，Y是两个随机变量，则有E(X+Y)=E(X)+E(Y)
D.设X，Y是相互独立的随机变量，则有E(XY)=E(X)E(Y)
