If you get into the forest with your friends, stay with them always. If you don't, you may get lost. If you really get lost, this is what you should do. Sit down and stay where you are. Don't try to find your friends--let them find you by staying in one place. There is another way to help your friends or other nearby people to find you. Give them a signal by shouting or whistling three times. Any signal given three times is a call for help. Keep up shouting or whistling always three times together. When people hear you, they will know that you are not just making noise for fun. They will let you know that they have heard your signal. They give you two shouts, two whistles, or two gunshots . When someone gives you a signal, it is an answer to a call for help. If you don't think that you will get help before night comes, try to make a little house--cover up the holes with branches with lots of leaves. Make yourself a soft bed with leaves and grass. What should you do if you get hungry or need drinking water? You would have to leave your little house to look for a river. Don't just walk away. Pick off small branches and drop them as you walk so that you can find your way back. The most important thing to do when you are lost is to stay in one place. This passage mainly tells you  _  .
when you hear a signal always three times, it is a call for help what you should do if you get lost in a forest any signal given twice means an answer to a call for help how you can live longer in a forest