问题
选择题
人们在家中利用天线能接收到电视塔发射的载有电视信号的
A.超声波
B.次声波
C.电磁波
D.可见光
答案
答案:C
本题涉及的知识是电磁波。声波和光在空气中传播的距离较小,为了使电视信号有较大覆盖面积,通常利用电磁波来传播电视信号。
人们在家中利用天线能接收到电视塔发射的载有电视信号的
A.超声波
B.次声波
C.电磁波
D.可见光
答案:C
本题涉及的知识是电磁波。声波和光在空气中传播的距离较小,为了使电视信号有较大覆盖面积,通常利用电磁波来传播电视信号。
补全对话(从七个选项中选出五个,完成以下对话)。 | |
B: Yes, I have been there many times. A: 2 . B: Yes, I like the city very much. She's coming one of the most modern cities in the world. A: 3 . B: The city is clean and beautiful. The people are kind and the football team is strong. A: 4 . B: No, not very hot. You may have a swim in the sea. A: How cool! Swimming in the sea must be more wonderful than in the lake. B: I'm sure you'll have a good time there. A: Would you please go with me? B: 5 . A: What a pity! |