找考题网-背景图
单项选择题

A．the problems caused by river waterB．the necessity to ……

案例分析题

In some countries in which there is very little rain at any time，the farmers have to water their fields.Irrigation is easy enough if there is a great river near the crops and if there is plenty of water in it.Canals（运河）carry the river water to the fields when necessary.In some seasons there may be too much water in the river，and the water may flood all the land near it.At other times the river water may not be enough for all the farmers，and then it will be difficult to irrigate the fields.
To prevent these difficulties，a dam （大坝）may be built across the river.This will store water for dry seasons and in wet seasons it will prevent the flooding of the land.A great lake will，no doubt，be formed behind the dam，and this may mean that houses and fields will be covered with water.Most people will accept that and will be ready to move to other places.Then the country can have the right amount of water at all times；more crops will be growing，there will be more food for everyone，and there will be no more floods.
Dams have been built for centuries in different parts of the world.Modern dams are usually built of concrete（混凝土），but earth dams were used in India and Sri Lanka about 2，500years ago.There was another across the River Tigris very long ago，and large numbers of irrigation canals were made in Iraq to irrigate the land.The Romans were great dam-builders and there was also a famous dam at Ma’rubin Arabia.

The first paragraph mainly talks about （）.

A．the problems caused by river water
B．the necessity to irrigate the field
C．the water shortage in some countries
D．the canals carrying water to fields

<上一题 目录 下一题>
热门试题

单项选择题According to these two letters, which of the following statements is true?（）

A．Confused was glad to visit his roommate's house.
B．Confused was a little worried because he had no money for presents.
C．Confused should arrive at his roommate's house as late as possible.
D．Confused should eat the food up even if he didn't like the food.

未分类题A．Leave for home.B．Check the language lab.C．Buy a new locks.D．Show the man where the lab is.

未分类题A．It has numerous traits in common with the spotted owl.B．Its population is increasing.C．It may not survive without special efforts of conservationists.D．Its role in the chain of evolution has not yet been examined.

单项选择题假如两种物品之间的交叉弹性为-3，那么，第一种物品涨价，会使： A．第二种物品的需求曲线右移 B．第二种物品的需求曲线左移 C．第二种物品的需求量沿着该物品的需求曲线下移 D．对第二种物品的需求曲线的影响不确定

A.第二种物品的需求曲线右移

B.第二种物品的需求曲线左移

C.第二种物品的需求量沿着该物品的需求曲线下移

单项选择题正常货是指它的： A．价格弹性大于0 B．价格弹性小于-1 C．收入弹性大于1 D．收入弹性大于0

A.价格弹性大于0

B.价格弹性小于-1

C.收入弹性大于1

单项选择题假如总收入TR=300Q-30Q2，Q=5，那么，价格弹性为：（）

A.0
B.-1
C.-10
D.不确定

单项选择题Arabs will（）in a business meeting.

A．spend some time being polite and offering refreshments first
B．ask you to wait for several minutes first
C．introduce you to some strangers first
D．start talking business immediately

单项选择题完整的原型化的工具，应具有几个基本成分。以下成分：Ⅰ．集成数据字典Ⅱ．高适应性的数据库管理系Ⅲ．非过程查询语言和报告书写器Ⅳ．自动文档编辑器 Ⅴ．屏幕生成器 哪个(些)是原型化工具应该具备的?（）

A．Ⅰ和Ⅴ
B．Ⅰ和Ⅳ
C．Ⅲ和Ⅳ
D．全部

未分类题A．胸骨左缘第2肋间可闻及Ⅳ级连续性机器样杂音 B．胸骨左缘3～4肋间可闻及Ⅳ级左右收缩期杂音 C．胸骨左缘2～4肋间可闻及I、Ⅱ级左右收缩期喷射音 D．胸骨左缘2—3肋间可闻及Ⅲ级收缩期喷射音，肺动脉瓣区第二音亢进固定性分裂 E．心尖部可闻及Ⅱ级收缩期杂音动脉导管未闭

单项选择题当需求价格弹性小于1时，边际收入为： A．负值 B．正值 C．0 D．正值，但小于1

A.负值
B.正值

C.0

未分类题A．Its scarce proteins.B．Its terrible taste.C．Its many vitamins.D．The difficulty of finding it.

单项选择题假如Qx=20-0.5Px+0.1I-2.0Py，Py=2和Qx=10，那么x的交叉弹性为： A．-0.2 B．-0.4 C．-0.04 D．0.4

A.5Px+0.1I-2.0Py，Py=2和Qx=10，那么x的交叉弹性为：

B.-0.2
C.-0.4
D.-0.04

单项选择题假如Qx=20-0.5Px+0.1I-2.0Py，物品x和物品y为： A．替代品 B．互不相关 C．低档货 D．互补品

A.5Px+0.1I-2.0Py，物品x和物品y为：

B.替代品
C.互不相关
D.低档货

未分类题A．look upB．look downC．look awayD．lo0k back

未分类题听力原文：W: Hey! The train is late! I've been waiting her for ages.M: Which train, madam?W: The 8:18 to Baker Street.M: The 8:187 I'm afraid you've made a mistake, madam.W: A mistake? My timetable says: Baker Street train—8:18.M: Oh, no, madam. The Baker Street train leaves at 8: 08.W: At 8:08?M: You see, madam. They changed the timetable at the end of April.W: Changed it? May I see the new timetable? What does it say?M: It says: Baker Street train—8:08.W: Hm! So the train isn't late. I'm late.(13)A．Because the train was late.B．Because the train was canceled.C．Because she didn't know the timetable was changed.D．Because she was late.