设计一个大型信息系统首先必须有A．一个原型系统作参考 B．一个系统规划作指导 C．一

玻璃钢门窗与传统的钢门窗和木门窗相比，具有（）等特点。

A.不宜成型

B.质量大

C.耐腐蚀性好

D.抗冻性好

E.绝缘性好

在一个圆锥的体积不变的条件下，若它的高缩小9倍，底面半径应[ ]

A．扩大9倍    

B．缩小9倍    

C．扩大3倍    

D．缩小3倍

LTE系统下行峰值速率150Mbps是根据怎样的天线设置定义的？（）

A.下行峰值速率指标需要在UE配置2个接收天线的情况下满足

B.下行峰值速率指标需要在基站配置2个接收天线的情况下满足

C.上行峰值速率指标需要在UE配置1个接收天线的情况下满足

D.上行峰值速率指标需要在基站配置2个接收天线的情况下满足

我国现在制定和修改法律要问计于民，重大规划及关系民生项目建设、价格调整要征求民意，人大常委会及政府会议公民可以旁听，人民可以通过多种渠道提出建议。这些现象产生的根本原因在于[ ]

A．我国民主的广泛性、真实性

B．民主具有鲜明的阶级性

C．民主与专政对立统一

D．我国的国体

阅读理解。

     Getting your teen to think beyond his own immediate needs can be more difficult than cracking a nut

with a plastic fork.But don't worry. It's not impossible.There are many ways to encourage your teen to

care about those outside his immediate circle of friends. As he begins to have responsibility towards others,

he will realize he feels even better about himself.

     "Teens are thinking about career, college, and what their future might look like," explains Michelle

Maidenberg, a clinical director of Westchester Group Works, a center for group treatment in New York.

 "This is very challenging and just one of the reasons why they are so focused on their own world." Once

teens participate in community service, however, they begin to look beyond their personal needs. They also

learn firsthand about the challenges others face, and they experience a sense of authority as they realize they

can make a real difference in others' lives.

     Not sure how to convince a teen to get away from the cell phone and into a community project? Teens

buy into community service when the project or program is in an area of their interest.

     "Finding something in an area of interest for them keeps them motivated and inspired," Maidenberg says.

For instance, if he is interested in culinary (烹饪) school, he could volunteer in a soup kitchen or bake for a

project that supports families in need.Volunteer projects in your teen's area of interest will build her

knowledge base as well as help others.

     Parents can do their part by participating in community service themselves. Teens can learn directly from

their parents that personal enjoyment is not, all that matters.

     Let teens know the benefits they will obtain." Give them every reason in the world to volunteer, " 

Maidenberg advises. She says that working on community service projects builds confidence." By working

with others, teens improve managerial, interpersonal and communication skills. Community service helps to

approach maturity when they take a step back to see the needs of other people," she adds. Another reward:

service hours look great on a resume!

1. According to Michelle Maidenberg, it's hard to get teens to think beyond their own immediate needs

partly because _____.

A. they care more about their circle of friends

B. they have no interest in doing anything

C. they have to work hard for college

D. they are facing many challenges

2. The underlined phrase "buy into" in Paragraph 3 probably means ______.

A. agree to join in

B. spend money on

C. get away from

D. are interested in

3. The writer mentions the benefits in the last paragraph in order to ______.

A. make teens feel much better about themselves

B. encourage teens to care about his own needs

C. help parents reason teens into volunteering

D. get parents to do more community service