题目

If you go into the forest with friends, stay with them. If you don’t, you may get lost. If you 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. You can help them find you by staying in one place. There is another way to help your friends or other people to find you. You can shout or whistle three times. Stop. Then shout or whistle three times again. 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关于重力的说法中错误的是A. 地面及附近的物体都受到重力B. 重力的方向总是竖直向下的C. 1kg=9.8ND. 重力是由于地球的吸引而使物体受到了力