福州科技馆展出的磁动轮是根据异名磁极相互吸引的原理制成的，每个轮的边缘装有12个侧放的柱形磁体，如图所示．当推动A轮转动时，其他3个轮会随之转动，若A轮磁体外侧是N极，则C轮磁体外侧是　 ____　极．如果A轮逆时针转动，C轮将 ____（填“顺”或“逆”，下同）时针转动，D轮将 ____时针转动．

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如图所示是人体部分器官系统及有关物质的代谢关系示意，其中的a、b、c、d、e、f、g分别表示不同的物质．请分析回答：

哥伦布始终相信地球是圆的，并百折不挠地开辟新航路，这说明新航路的开辟是（   ）

    Tom's school basketball game is next month. His class 1 a new player. His teacher asks him to be one. of the players 2 he is tall (高的). But Tom doesn't like 3 sports. He can't play basketball 4 and he thinks it is 5 for him, so he calls his friend Edward to help him. Edward says he'll help Tom 6 his basketball skills (技巧). They have about 20 days to prepare for (为……做准备) the game, and in the next three 7 they play basketball for 2 hours a day. They don't have much 8 at school, so they play it after the classes 9 .Tom is tired (疲倦的) but happy every day. Now, Tom loves 10 He thinks it is relaxing and fun.

汽车在平直公路上匀速行驶，下列说法正确的是（　　）