6、。阅读下面短文,从每题A、B、C、D四个选项中,选出一个能填入文中相应空白处的最佳答案。Radio, telephone and television are widely used in the world. When you 1 the radio, you can listen. But when you use the telephone, not only you can listen to others __2 you can talk with them. However, you 3 see anything at all. Television
7、is much better than 4 of them. People can watch TV and listen to it. But they can't take part in 5 they see.Today some people are using a kind of telephone called the picture phone or vision phone. 6 it two people who are talking can see each other.