阅读理解
Everybody knows that words can carry messages. People communicate(交流)with words. Books, magazines, TVs, radios and films all help us to communicate with others. They all help us to know what is going on in the world and what other people are thinking about.
Do you think you can communicate without words? A smile on your face shows you are happy or friendly. Tears in your eyes tell others that you are sad. When you put up your hand in class, the teacher knows you want to say something or ask a question. You shake your head, and people know you are saying “No”. You nod and people know you are saying “Yes”.
Other things can also carry messages. For example, a sign at the bus stop helps you to know which bus to take. A sign on the wall of your school helps you to find the library.
Signs on doors tell you where to go in or out. Have you ever noticed that there are a lot of signs around you and that you receive messages from them all the time?
People can communicate in many ways without words. For example, an artist can use his drawings to tell about beautiful mountains, the sea and many other things.
阅读短文, 判断正误(T/F)。
和
，绳子对物体的拉力为T，物体所受重力为G，则下面说法正确的是( )