阅读材料，回答问题。

材料一：武帝雄才大略，即位之初，卓然罢黜百家，令后学者有所统一。始分藩国，而子弟毕侯矣。

材料二：如果说从平城到洛阳的北魏是汉化先行者，那么西魏、北周就是追随者。……北周政权，折射出中华民族历史重新走向全国统一的曙光。……隋朝的统一，建立在魏晋南北朝民族大融合的基础之上。

在亚洲，中国、韩国和越南都有过春节的习俗，但三国春节的标志性习俗却各不相同：中国是对联、爆竹、饺子；韩国是祭拜祖先、米糕汤；越南是祭祖祭神、粽子炙肉。由此可见
①民族节日是民族文化的集中展示 ②世界文化具有多样性　③透过传统节日及习俗，可以让我们领略不同民族文化的韵味　④非物质文化遗产是一个国家历史文化成就的重要标志

小明打开冰箱门，发现冷冻室的侧壁有许多霜，这是水蒸气____（填物态变化）形成的，这个过程要____（填“吸收”或“放出”）热量。

湿地被称为“地球之肾”,最主要的原因是因为湿地具有(    )

    There are some easy things you can do to protect(保护) the environment and the earth. Choose ideas from the list or come up with a few of your own.
    ● Plant flowers, grass or trees.
    ●Whenever you visit a park or beach, take away what you bring there--keep rubbish in a bag until you can put it in a dustbin (垃圾箱).
    ●Turn off the lights, TV sets when you leave the room. This saves (节约)a lot of electricity.
    ●Turn off the tap (水笼头)when you brush your teeth. You can save some water by not letting it run. Also, use a glass cup instead of a paper cup because this saves paper.
    ●Keep the doors and windows closed in winter to keep warm air in.
    ●Give your old books and magazines to a library instead of throwing them away.
    ●Give your old clothes to poor children you know instead of throwing them away.
    ●Use both sides of paper.
    ●Stop pouring (倒)dirty water into the rivers or the lakes nearby (附近).
    ●Encourage all your friends to do the same things you do to help protect the earth.
    You don't have to wait until Earth Day to do these things. Make every day Earth Day.
    If everyone makes a contribution (贡献)to protecting the environment, the world will become much more beautiful.