如图所示，宇宙射线中存在高能带电粒子，假如大气层被破坏，这些粒子就会到达地球，从而给地球上的生命带来危害，根据地磁场的分布特点，判断下列说法中正确的是
A．地磁场对直射地球的宇宙射线的阻挡作用在南北两极最强，赤道附近最弱
B．地磁场对直射地球的宇宙射线的阻挡作用在赤道附近最强，两极最弱
C．地磁场对宇宙射线的阻挡作用在地球周围各处相同
D．地磁场对宇宙射线无阻挡作用
答案：B
补全对话(有一个多余选项)。
B: Yes, please. I am looking for a mobile phone, but I have no idea. A: We have got all kinds of mobile phones here. Which do you prefer, Siemens, Nokia or Motorola? B: I really know little about them. Which one sells best these days? A: Mm…__2__ B: How much is Motorola? A: __3__ The newer, the more expensive. B: __4__ A: What about this one? It looks nice and works well. B: How much is it? A: 1,000 yuan. B: Any discount? How about 850 yuan? A: __5__ That's the best we can do. OK? B: OK. I will take it. |