题目内容：

In your school bags, you may have a pencil, some kinds of pens, a ruler, and some books. None of these things grow in the fields. They were all made in factories. And, of course, they were invented by some people. There have not always been pencils or pens, a ruler and books. Thousands of years ago no one knew about these things.

Who invented them first? How did they have such clever ideas? We always don’t know. There have been many thousands of inventions, large and small, in the human history. Some of these inventions have changed the world. Such as paper, printing, radio, telephone and computer, and we know the inventors. But we have forgotten most of the other inventors.

Who invented the clock, for example, or the lock to the door? We don’t know. There have been thousands of inventors and we should grateful to them for their clever ideas. Will you be one of them when you grow up?

根据短文内容，选择正确答案

1.Most things in your school bags are made of _________.

A. paper    B. wood    C. metal    D. nylon

2.The inventors invented these things because _________.

A. their children were at school    B. they hoped to save some money

C. they have a lot of clever ideas    D. they have good machines

3.The history books tell us _________.

A. who invented paper and printing    B. who invented clocks and doors

C. when the first key was invented    D. how much the silk cost

4.We don’t know ________.

A. the names of the inventors of paper    B. the names of the inventors of telephone

C. the names of the inventors of lamp    D. the names of most inventors

5.The writer wonders _________.

A. if you are an inventor    B. if you want to be an inventor

C. what’s invented by you    D. how many inventors you know