According to the passage, signal, symbols, signs and gestures ______.

* Hướng dẫn giải

Dẫn chứng: Although signals, signs, symbols, and gestures are very useful, they do have a major disadvantage in communication. They usually do not allow ideas to be shared without the sender being directly adjacent to the receiver. Without an exchange of ideas, interaction comes to a halt. As a result, these means of communication intended to be used for long distances and extended periods must be based upon speech.