磁感应强度、带电粒子的电性和速度v的方向如图所示，其中带电粒子不受洛伦兹力的是（　　）

蒙古贵族召开大会，推举铁木真为成吉思汗，成立蒙古汗国是在 (      )

2011年5月19日从农业部渔业局了解到，尽管世界经济的不稳定性和区域间不均衡加剧，但由于我国已形成较为完整的加工产业链和稳定的出口渠道，加上日本核泄漏事件后日本和欧美等主要水产品进口国对我国需求增加，预计今年我国水产品出口贸易将保持较为平稳增长。这告诉我们
①经济全球化使世界各国的经济联系在一起，一国的经济波动可能殃及他国，甚至影响全世界  
②一种商品的需求量下降，它的替代品的需求量上升
③及时了解市场供求变化，以市场为导向进行生产经营
④改革开放以来，我们一直是以“走出去”为主

一定温度下可逆反应N₂（g）+3H₂（g）⇌2NH₃（g） 达平衡的标志是（   ）

    How dangerous it would be if there was a fire! Winter is the time for us to learn a lot more about fire, especially what to do if we are caught in a fire.

1. Shout out If you smell smoke or see fire, shout out “Fire!” Shout as loudly as you can, because people may be asleep.

2. Call 119 Never try to put out the fire yourself, even if it is a very small one! Get help from your parents or call 119.

3. Keep down close to the floor If there is a lot of smoke in your room, keep down close to the floor.

4. Test the door Test the door before you open it. If the door is cool, open it carefully. If the door is hot, do not open it! Try to find a different way out.

5. Get out If you can, get out of your home as soon as possible.

6. Don't use the lift Never use the lift during the fire. It may also go wrong.

7. Don't go back Never go back into a burning building!