发展中国特色社会主义文化的中心环节是（  ）

设P={x|x²﹣2x﹣3≤0}，a= $\sqrt{2}$ ，则下列关系中正确的是（   ）

    Have you ever heard of Jinjiang Hotel? It is on our busiest street. It's the best place to live in if you travel here. The hotel is only 0.5 kilometer from the biggest supermarket and the subway.

    It has three kinds of rooms for different people to use. The first kind is standard room, that is two beds with a bathroom. It offers you the air conditioner, the television and the telephone. Second is the single room, that has only one bed. Though it has only one bed, you can enjoy yourself, for the bed is really comfortable and the environment is really good. The last one we call commercial room. That is served for businessmen. The commercial room has the best quality. It also provides 24-hour hot water. You can have free tea in the afternoon. Imagine how nice as you drink tea as talking about your business with your partners. If you want to eat something, please just call 123, the food will arrive in ten minutes.

    One great thing is that it is very safe here because we have a few strong guards working day and night, so I'm sure you will have a great time living here.

下面一段文字是某留学中介公司的广告，在表达上有不得体之处，请指出并改正。

    楚天留学服务公司以“精准定位，精致服务”为服务宗旨，长年致力于国际教育交流、出国留学咨询、签证办理等业务。我公司留学顾问均有留学背景和丰富经验，针对您的疑问将不吝赐教，并帮助量身打造个性方案，在任何您需要的环节鼎力相助，圆您留学梦想。店庆期间，服务费九折并惠赠《留学指南》一本，欢迎垂询惠顾。

①“____”改为“____”；②“____”改为“____”；③“____”改为“____”