Cross Polo的胎压检测系统可以同时发现4个轮胎漏气信息，检测到胎压下降（）以

命题“若一个数是负数，则它的平方是正数”的逆命题是(        ).

A．“若一个数是负数，则它的平方不是正数”

B．“若一个数的平方是正数，则它是负数”

C．“若一个数不是负数，则它的平方不是正数”

D．“若一个数的平方不是正数，则它不是负数”

阅读理解.

                                                The World's Water Shortage

    The world is not only hungry, but it is also thirsty for water. This may seem strange to you, since

nearly 70 percent (百分比) of the earth's surface is covered with water. But about 97 percent of this

huge amount is sea water, or salt water. Man can only drink and use the other 3 percent－the fresh

water from rivers, lakes, underground, and other sources (资源). And we cannot even use all of that,

because some of it is in the form of icebergs and glaciers (冰川). Even worse, some of it has been

polluted.

    However, as things stand today, this small amount of fresh water is still enough for us. But our need

for water is increasing (增加) rapidly－almost day by day. Only if we take steps to deal with this

problem now can we avoid (避免) a severe (严重的) worldwide water shortage later on.

    We all have to learn how to stop wasting our valuable water. One of the first steps is to develop ways

of reusing it.

    Today in most large cities, water is used only once and then sent out into a sewer system (下水道).

From there it returns to the sea or runs into underground storage tanks. But it is possible to pipe used

water to a purifying (净化) plant. There it can be treated with chemicals so that it can be used again,

just as if it were fresh from a spring.

    But even if every large city purified and reused its water, we still would not have enough. All we'd

have to do to make use of the vast reserves (贮备) of sea water in the world is to remove the salt.

    If we take these steps we'll be in no danger of drying up.

1. The world is thirsty for water because we can only use _____ percent of the water covering the

surface of the earth.

    A. 3

    B. more than 3

    C. less than 3

    D. 97

2. Which of the following statements is Not true?

    A. As things remain unchanging, this small amount of fresh water is still enough for us.

    B. Our need for water is becoming larger and larger.

    C. There will be no water shortage in the future.

    D. We should take steps to deal with the water shortage problem.

3. To reuse water, we should _____.

    A. treat it with chemicals

    B. use it only once

    C. send it out into a sewer system

    D. make it flow into underground tanks

4. In order to have enough water, we should also make use of _____.

    A. icebergs and glaciers

    B. sea water

    C. rivers and lake

    D. underground water

5. In the passage, the writer tells us _____.

    A. to make enough water

    B. to pay more attention to the water shortage problem

    C. to pipe used water to a purifying plant

    D. to reuse the water

原始生命具有的基本特征是（　　）

A．能运动

B．能进行细胞分裂

C．由有机大分子构成

D．能生殖和遗传

三标一体认证是（）年通过的。

A.2005

B.2004

C.2003

D.2002

下列罪犯分级处遇降级情形正确的有（）。

A、严重违反监规纪律一次性被扣2分（含2分）以上，月累计扣3分以上（含3分）的，或受到警告处分的，由现处遇级别下降一级

B、普管级以上罪犯连续3个月没有获得3分基本分的，处遇由现级别下降一级

C、受到警告以上处分的，一律降至四级严管

D、重新犯罪正在接受处理或受到加刑处罚的罪犯，一律降至严管级

E、假释、监外执行期间有违纪、违法行为被收监的，一律降至严管级