一质量为M，长为ι的均匀细杆AB吸引着一质量为m的质点C，此质点位于杆AB的中垂线上

物资生产过程的功能是创造物资的（）。

A.形质效用

B.时间效用

C.空间效用

D.社会效用

阅读理解。

     We may all have had the embarrassing moment: Getting half-way through a story only to realize that we've

told this exact tale before, to the same person. Why do we make such memory mistakes?

     According to research published in Psychological Science, it may have to do with the way our brains

process different types of memory.

     Researchers Nigel Gopie, of the Rotman Research Institute in Toronto, and Colin Macleod, of the University

of Waterloo, divided memory into two kinds. The first was source memory, or the ability to keep track of

where information is coming from. The second was destination memory, or the ability to recall who we have

given information to.

     They found that source memory functions better than destination memory, in part because of the direction

in which that information is travelling.

     To study the differences between source and destination memory, the researchers did an experiment on 60

university students, according to a New York Times report. The students were asked to associate (联想) 50

random (随意的) facts with the faces of 50 famous people. Half of the students "told" each fact to one of the

faces, reading it aloud when the celebrity's (名人的) picture appeared on a computer screen. The other half

read each fact silently and saw a different celebrity picture afterward.

     When later asked to recall which facts went with which faces, the students who were giving information

out (destination memory) scored about 16 percent lower on memory performance compared with the students

receiving information (source memory).

     The researchers concluded that out-going information was less associated with its environmental context

(背景) that is, the person-than was incoming information.

     This makes sense given what is known about attention. A person who is giving information, even little facts,

will devote some mental resources to thinking about what is being said. Because our attention is limited, we give

less attention to the person we are giving information to.

     After a second experiment with another group of 40 students, the researchers concluded that self-focus is

another factor that undermines destination memory.

     They asked half the students to continue giving out random information, while the other told things about

themselves. This time around, those who were talking about themselves did 15 percent worse than those giving

random information.

     "When you start telling these personal facts compared with non-self facts, suddenly destination memory

goes down more, suggesting that it is the self-focus component (成分) that's reducing the memory," Gopie

told Live Science.

1. The point of this article is to _____. [ ]

A. give advice on how to improve memory

B. say what causes the memory to worsen

C. explain why we repeat stories to those we've already told them to

D. discuss the differences between source and destination memory

2. What can we learn from the article? [ ]

A. Source memory helps us remember who we have told the information to.

B. One's limited attention is one of the reasons why those reading aloud to the celebrity's pictures perform 

    worse on the memory test.

C. Silent reading is a better way to remember information than reading aloud.

D. It tends to be more difficult for people to link incoming information with its environmental context than 

    outgoing information.

3. The underlined word "undermines" probably means _____. [ ]

A. weakens

B. benefits

C. explains

D. supports

4. What did the scientists conclude from the second experiment? [ ]

A. Destination memory is weaker than source memory.

B. Focusing attention on oneself leads to relatively poor source memory performance.

C. Associating personal experience with information helps people memorize better.

D. Self-focus is responsible for giving information twice or more to the same person.

下列风险中，属于房地产投资系统风险的是( )。

A．通货膨胀风险
B．收益现金流风险
C．未来运营费用风险
D．时间风险

Is there enough ______ for me in the car
[A] place[B] room [C] seat

在进行分类汇总时，可设置的内容有：（）

A、分类字段

B、汇总方式（如：求和）

C、汇总项

D、汇总结果显示在数据下方