Many animals use some kinds of "language".They use signals (信号) and the signals have meanings.For example,（1）a bee has found some food,it goes back to its home.It is difficult for a bee to tell（2）bees where the food is by speaking to them,but it can do a ltte dancing.This tells the bees where the food is and how far away it is.Some animals show how they feel by making sounds.It is not difficult to tell if a dog is angry because it barks.Birds makeseveral different sounds and（3）has its meaning.Sometimes we humans make sounds in the same way.We make sounds like "Oh!" or "Ouch!" to show how we feel about something or we（4） something on our feet.We humans have languages.We have words.These words have meanings.We are able to give each other information,to tell other people what we think or feel.By writing downwords,we can remember what has happened or 5 messages to people far away.1.A.sinceB.whyC.becauseD.when2.A.the otherB.anotherC.othersD.each other3.A.someB.eachC.everyD.all4.A.setB.fallC.putD.drop5.A.getB.bringC.sendD.catch