上消化道出血表现为呕血或黑便，主要取决于（） A.出血的速度和量 B.出血部位的高低

Imagine the situation. You are driving in a village or on a mountain. You have no idea where you are. You passed the last house two hours ago. Then your car doesn’t work. It is night and it is cold. You have no mobile phone. What do you do? Well, next time take a GPS with you. This invention may be able to help you. It is used for finding your position(位置) with the help of satellites (卫星). A GPS can’t start your car, but at least you will know where you are.

GPS, which means Global Positioning System(全球定位系统), is a small radio receiver. It looks like a mobile phone. You can hold it in your hand, or put in your pocket. It is sometimes put into a watch or a telephone. We also find a GPS in cars, planes, or boats. Some of them have electronic maps, so you know where you are. For example, in a city they can tell you the name of the street.

There are three parts to GPS. The first part is the receiver. You can hold it in your hand, or have it fixed into your car, plane, etc. The second part is a group of satellites going around the Earth. The receiver communicates with at least four of the satellites and calculates its position. The third part of the system is a network of ground stations all over the world. They control (控制) the satellites and make sure they are working well.

Some people think that in the future the GPS will be as common as the mobile. They are becoming better and cheaper. There are also new uses for the GPS. Perhaps they will become like watches. Everyone will have one and you will never be lost again.

小题1:According to the passage, with the help of the GPS, people __________.

A．can’t be lost in a new city

B．can’t find their way in different countries

C．can learn about the culture of an unknown place

D．can spend the least time getting to another place小题2:We can learn from the passage that ____________.

A．there are three parts to the GPS

B．a GPS can’t be put into a watch

C．a GPS can help you start your car

D．the GPS are becoming more and more expensive小题3:The underlined word “They ” in paragraph 3 means “____________”.

A．Receivers

B．GPS

C．Satellites

D．Ground stations小题4:What can we infer(推断) from the passage?

A．All GPS devices have electronic maps.

B．People in many countries will use the GPS for free.

C．The receiver of the GPS communicates with at least five of the satellites.

D．The GPS will become more and more common in everyday life.

政府通过制定合适的流通产业政策，适度地为消费者提供需要的商品或服务，就可以实现充分就业，物价稳定，国际收支平衡，经济持续增长，这是流通产业政策的（）目标。

A.经济发展

B.经济稳定

C.经济自由

D.经济公平

（1）在用两面平行的玻璃砖测定玻璃折射率的实验中，其实验光路如图所示，对实验中的一些具体问题，下列意见正确的是(　　)

A．若P₁、P₂的距离较大时，通过玻璃砖会看不到P₁、P₂的像

B．为减少测量误差，P₁、P₂的连线与玻璃砖界面的夹角应尽量大些

C．为了减少作图误差，P₃和P₄的距离应适当取大些

D．若P₁、P₂连线与法线NN′夹角较大时，有可能在bb′面发生全反射，所以在bb′一侧就看不到P₁、P₂的像

（2）图1所示为光学实验用的长方体玻璃砖，它的光学面面不能用手直接接触。在用插针法测定玻璃砖折射率的实验中，两位同学绘出的玻璃砖和三个针孔a、b、c的位置相同，且插在c位置的针正好挡住插在a、b位置的针的像，但最后一个针孔的位置不同，分别为d、e两点，如图2所示。计算折射率时，用________(填“d”或“e”)点得到的值较小，用________(填“d”或“e”)点得到的值误差较小。

蓄电池点火系电路分哪两部分（）。

A、低压电路和高压电路

B、低压电流和高压电流

教学时，列举与学生的社会文化背景有关的例子尤为有效这是由于强化动机中的（）

A.保持好奇心

B.使用大量有趣的呈现方式

C.帮助学生建立自己的目标

D.激发兴趣