长江沿江地带和黄土高原地区共有的环境问题是（　　）

①缺水断流     ②水污染     ③旱涝     ④水土流失     ⑤凌汛

如图所示，用来研究通电导线在磁场中受到力的作用的实验装置是（）

    2014 is the year of horse in China. Do you know anything about the horse?

    The horse is strong and runs very fast. He's a useful and hard-working animal. The horse learns to know his owner soon. He loves his owner, even after his owner loses his life. Here's a story about such a horse. In a war, the owner passed away(死), and fell from his horse. When people found his body some days later, the horse was still standing beside it. During that long time, the horse didn't leave the body of his owner, without food or water, in the coldest weather, driving away the birds that might eat it. Wasn't he a great animal?