问题 阅读理解

B

You’re shopping for a high-priced product, but have limited money. How to make the best use of your money? Here are some steps you can take to become a smart shopper.

Step 1. Before buying a high-cost product, think about:

·why you are buying the product

·how often and when you will use the product

·what the main use of the product is

·why you need this product now, not later

Step 2. To choose the best product, you need to research and find out:

·what companies make the product

·the differences in each company’s product

·what others say about the product

It can be very helpful to know what other people say about a product you want to buy. Product reviews often describe problems. Reviews also tell how people use the product. List product information so that you can refer to it before you decide to buy

Step 3. To find the best price for the product you want to buy, you need to compare:

·prices of the product

·brand(商标) names and store names

·places to buy your product (in stores, online, etc.)

·product labels(标签) and information

Step 4. As you get ready to buy, search your local newspaper and the Internet for special offers. Many sales are offered around holidays or at the end of a season. Wait to see if there will be a holiday or end-of-season sale before you buy. Check to see if you can get a lower price for the product you want to buy.

These steps will help you become a smart shopper. If you follow them, you should get the best deal. Remember, the more you know, the less someone can take advantage of you.

60. This is a piece of advice for those who want to buy________.

A. advertised goods                         B. goods on sale

B. online products                           D. expensive products

61. Why should you go through related product reviews before shopping?

A. To decide where to buy the product.

B. To find out why you need the product.

C. To find shops offering best price for the product.

D. To have a full knowledge of the product

62. Which of the following is the CORREST order of smart shopping?

a. Watching for sales.

b. Finding out your purpose of shopping.

c. Researching your product.

d. Making comparisons before shopping.

A. b c d a                  B. b d c a                     C. c d a b                     D. c a d b

答案

60---62   DDC  

问答题

某同学在探究物体弹性碰撞的特点时,先提出了如下假设:①两个物体碰撞前后各自的质量与自己的速度的乘积之和是不变的;②两个物体碰撞前后各自的质量与自己速度的二次方的乘积之和是不变的.为了验证这个假设,该同学设计了如图1所示的实验装置.先将弹性a球从斜槽轨道上某固定点处由静止开始滚下,在水平地面上的记录纸上留下压痕,重复10次;再把同样尺寸大小的弹性b球放在斜槽轨道末端水平段的最右端附近静止,让a球仍从原固定点由静止开始滚下,和b球相碰后,两球分别落在记录纸的不同位置处,重复10次.

(1)在安装斜槽轨道时,要注意______.选择弹性小球a、b时,小球a、b的质量ma、mb应该满足关系:ma______mb(填“>”或“=”或“<”),理由是______.

(2)本实验必须测量的物理量有以下哪些______.

A.斜槽轨道末端到水平地面的高度H

B.小球a、b的质量ma、mb

C.小球a、b的半径r

D.小球a、b 离开斜槽轨道末端后平抛飞行时间t

E.记录纸上O点到A、B、C各点的距离SOA、SOB、SOC

F.a球的固定释放点到斜槽轨道末端水平部分间的高度差h

(3)该同学设计了一个实验数据表格,见表一.从表中可以看出,有些物理量并非实验中直接测出的,请你将表中不能直接测出的物理量换成能直接测出的物理量,而不影响实验探究的目的,并将结果对应填在表二中.

表一:

碰撞前碰撞后
质量mamamb
速度vav’av’b
mvmavamav’a+mbv’b
mv2mav2amav’2a+mbv’2b
表二:

碰撞前碰撞后
质量
速度
mv
mv2
(4)为测定未放被碰小球时,小球a落点的平均位置,把刻度尺的零刻线跟记录纸上的O点对齐,图2给出了小球a落点附近的情况,由图可得OB距离应为______cm.

(5)该同学通过对实验数据的分析和处理验证了他的假设,这就表明物体在弹性碰撞中有两个物理量是守恒的,这两个物理量分别是______、______.

单项选择题 案例分析题