空气中体积分数约占78%的气体是（ ）

将我国领土四端点与其位置相匹配：

最北端____      a 新疆帕米尔高原

最南端____      b 黑龙江与乌苏里江主航道中心线的相交处

最西端____      c 漠河以北的黑龙江主航道中心线

最东端____      d 南沙群岛的曾母暗沙

率船队首次完成环球航行的航海家是(       )

    Last year, my best friend, Li Xiaoming, talked about the best way of studying English. At first he thought the teacher spoke 1quickly2he didn't understand. He also3 ask questions4 his poor pronunciation. Then he began to watch English movies, he 5 funny movies.6 he couldn't understand everything the characters said,7he can get the meaning by watch body language and expressions. He also realized he could get the meaning by8 for the key words. His pronunciation improved as well by listening to the conversations in English movies. Sometimes he learned some9sentences like “It's a piece of cake.” At last he often 10 the new words in the dictionary.