4. 他们经常把这些标记串在细绳上，以便他们能容易地 随身携带它们。

They often put the tokens on pieces of string _

____them around easily.

3. 然后人们开始使用用陶土或小石头制成的标记。

Then people began to use tokens__clay or

small stones.

2. 他们用它们来数像每月的天数、食物的数M和他们拥 有的动物的数量这类东西。

They______the

days of the month, the amount of food and ihe number of animals they had.

1. 然而，用这种方法，他们只能数小数字。

However, they could only count small numbers _

1. 起初_

2. 这样;用这种方法__

3. 为了；以便_

4. ……的数量_

5. 导致_        

6. 发展成为_

I. 发明n._ 2.不同的adj._

3.手指n._ 4.然而adv_

5.计算总数v._ 6.动物n_

7.细绳n_ 8.工具n._

9.系统n. 10.算盘n

Mosl people have their jobs.They go to work 1 every day.Some people are lucky. Either they have very interesting jobs or they make a lot of money. Most people are not so hicky.Either their jobs are not very interesting or they don't make 2 money• The most interesting jobs are often the most (liffirult. I、'"ple spend a long time 3 how to do them.Doctors study for at least six years after 4 school.

Some young people have interesting and high-pay jobs. Many voung players do their work successfully. Football and tennis stars arc usually under 35 years old.Older people usu?ally cannot play these sports very 5 • They cannot move fast 6 Golf, however, is a good sport for older people. Many golf players are 7 old.Bui they can play it success?fully.

Mosl people work 8 they are 60 or 65 years old. Then they retire (退休)ami have a lol of 9 time. Some people never retire though. These people usually have very interesting jobs. Writers, artists, scientists and actors usually work until they die.Their work is 10 life.

1._ 2,_ 3._ 4._ 5._

3. 为使他的课有趣，他用了很多游戏：（make sth.interest-ing)