某人向正东方向走$xkm$后，向右转$150°$，然后朝新方向走$3km$，结果他离出发点恰好是$\sqrt{3}km$，那么$x$的值为（   ）

A

    It looks like there are more cats around us today. In fact, now there are about 58.1million pet cats in China. China has the second largest number of cat owners in the world 1 the United States. Every year, more young people take cats as pets.

    More cats bring more 2. Many people now work at pet shops and animal hospitals. But cats can become 3, too. Some people throw their pet cats away. Then the cats become 4. They can pass on diseases（疾病）, and they kill other animals like birds and frogs.

    So in Japan and Australia, the governments 5 homeless cats to animal hospitals. Doctors operate on them. So the cats can't have babies. In this way, the number of cats will not go up.

下列能正确表示食物链的是（  ）

阅读下面的文字，根据要求作文。
       没有人一生都能尽善尽美，学习上、生活中我们都留下过遗憾。“遗憾”就像一个影子一样伴随着人的一生，又像一根绳索，串起了人生的喜怒哀乐。“遗憾”令人难受，但反思“遗憾”，如同含着一枚青橄榄，又何尝不会品尝到丝丝甘甜？反思学习上的遗憾，可以获得教训或向上的动力；反思生活中的遗憾，可以让人世间美好的情感荡涤心胸；反思为人处事的遗憾，可以帮助我们理解他人，加深友谊，懂得道理……所有的苦痛都会成为过去，如今该做的只有反思遗憾，不让曾经的遗憾重演。
       想一想，往事给你留下了怎样的遗憾？请以“曾经的遗憾”为题写一篇记叙文。

       要求：①文中不要出现校名及人名，如必须出现一律用“X X X”代替； ② 不少于600字。