“创造出比较鲜明民族特点和个性的优秀作品，要对博大精深的中华文化有深刻的理解，更要有高度的文化自信。”下列对文化自信理解正确的是（   ）

A: Mum, I have finished my homework .____ .
B: Of course .Which is your favorite TV program ?
A: Sports .It is said there will be a wonderful football match on TV tonight .
B: ____ 
A: A Chinese team will play against a Japanese team .
B: ____ 
A: I'm not sure . Ball games are usually shown on Channel 8.
B: ____ 
A:Well , it must be on Channel 6 then . Try that .
B: Here it is .____  Let's watch it together .
A: That's all right.

 根据下面提供的图文信息，简要写出其蕴含的物理知识．

甲：____ ；乙：____ ；丙：____ ．

20世纪50年代，一位农民创作了一首“稻谷赶黄豆，黄豆象地瓜，芝麻赛玉米，玉米比人大”的民歌，你认为这首民歌创作的时代是（    ）