SI导出单位是用Sl基本单位以（）形式表示的单位。 A.运算 B.代数 C.计算 D

Taking away a city’s rubbish is a big job. Every day trucks come into a city to collect it. Most rubbish is made up of things we can’t eat or use. If we kept these things, we would soon have a mountain of rubbish.

In some cities the rubbish is collected and taken outside of city to a dump. Often the city dump is placed where the ground is low or there is a big hole. The kitchen rubbish is broken into small pieces and sent into the sewage system. The sewage system takes away the used water from toilets, bathtubs and other places.

To keep mice and flies away, some earth is used to cover the newly dumped rubbish. Later, grass may be planted on the rubbish-filled land. Finally , a house or a school may be built there, and then you’d never know that this had once been an old rubbish dump.

In other cities the rubbish is burnt in special places. The fire burns everything but the metal. Sometimes the metal can be used again in factories where things are made of metal. The food parts of rubbish are put in special piles where they slowly change into something called humus, which looks like black earth. It is rich with kinds of things that feed plants and help make them grow.

小题1:The underline word “sewage” in the passage means_______

A．排污

B．染色

C．洗涤

D．洗尘小题2:How can we keep the mice and flies away?

A．Some water is used to cover the rubbish.

B．Some earth can be used to cover the rubbish.

C．The fire burns the rubbish.

D．The sewage system takes away the rubbish.小题3:According to the passage, the food parts of rubbish can be used again_______.

A．to feed animals

B．to feed plants

C．to build a house

D．to make machines小题4:How should we take care of a used metal box according to the passage?

A．By burning it off

B．By putting it in water

C．By throwing it away

D．By reusing and recycling it.小题5:The main idea of the passage is ______

A to let us know taking away rubbish is a big job.

B. to explain the need for rubbish collection

C. to introduce different ways to treat rubbish

D. to tell people to take useful things out of rubbish

如图所示，小灯泡标有“6V 3.6W”，电源电压为9V．闭合开关S，把滑动变阻器的滑片P移到R的中点时，小灯泡正常发光，试求：（不考虑温度对小灯泡电阻的影响）

（1）小灯泡的电阻；

（2）滑动变阻器R的最大阻值；

（3）当滑动变阻器滑片P移到a端时闭合开关S，小灯泡此时的功率为多大？

下列关于设计和施工总承包组织的说法，不正确的是( )。

A．永久组织又分两类：一类拥有设计和施工力量，可以专门承包某一类型或某一体系的建设项目；另一类只有管理人员，只进行建设项目总承包管理

B．临时组织又可以分为以设计为主体和以施工为主体两种形式，国外主要是以设计为主

C．在民用建设的项目中，项目总承包单位大多数是临时性组织

D．国外承担设计和施工总承包组织结构一般有两种形式：一种是永久性组织，即永久性的经济实体；另一种是临时性组织，即针对一个具体的建设项目，由若干个设计单位和施工单位组成的临时性组织

对破伤风梭菌叙述正确的是（）

A.通过伤口感染，细菌侵入血而致病

B.革兰阴性菌，具周鞭毛

C.不能形成芽胞

D.芽胞抵抗力强

E.致病物质主要是内毒素

透视的类型一般可以分为（）。

A.光影透视

B.大气透视

C.消灭透视

D.球面透视