A rabbit is running into its hole. You may ask, “What happened?”
Well, when a rabbit sees something dangerous, it runs away. Its tail moves up and down as it runs. When other rabbits see this tail moving up and down, they run too. They know that there is danger. The rabbit has told them something without making a sound. It has given them a signal.
Many other animals use this kind of language. When a bee found some food, it goes back to his home. It cannot tell the other bees where the food is by speaking to them, but it does a little dance in the air. This tells the bees where the food is.
Some animals say things by making sounds. A dog barks, for example, when a stranger
comes near. A cat purrs (发出呼噜呼噜的声音)when pleased. Some birds make several different sounds, each with its own meaning.
But human beings have something that no animals have –-- a large number of words about things, actions, feelings or ideas. We are able to give each other information, to tell or inform other people what is in our mind or how we feel. By writing words down we can remind ourselves of the things what have happened, or send messages to people far away. No animals can do this. No animals has the wonderful power of language.
No one knows how man learned to make words. Somehow he learned to make them. As centuries went by, he made more and more new words. This is what we mean by language.  People living in different countries made different kinds of words. Today there are about fifteen hundred different languages in the world. A very large English dictionary, for example,  contains four or five hundred thousand words. But we do not know all these. The words we know are called vocabulary. We should try to make our vocabulary larger. Read as many books as possible. When we meet a new word, look it up in the dictionary. A dictionary is the Most useful book.
【小题1】 When a rabbit gives the other rabbits a signal of danger, it _______.

Put an ice cube from your fridge into a glass of water. You have a piece of string(线) 10 centimeters long. The problem is to take out that piece of ice with the help of the string. But you must not touch the ice with your fingers.
You may ask your friends to try to do that when you are having dinner together. There is a saltcellar on the table. You must use salt when you carry out this experiment.
First you put the string across the piece of ice. Then put some salt on the ice. Salt makes ice melt(融化). The ice round the string will begin to melt. But when it melts, it will lose heat. The cold ice cube will make the salt water freeze(结冰) again.
After a minute or two you may raise the piece of string and with it you will raise your piece of ice!
This experiment can be very useful to you. If, for example, there is ice near the door of your house, you must use very much salt to melt all the ice. If you don’t put enough salt, the water will freeze again.
【小题1】We must use           when we carry out this experiment.

----Jack, Can I use your bike?

----Sorry. I have _______ it _______ Nick. You may ask Sam.

A．borrowed; from    B．lent; to           C．kept; for          D．returned; to