若 x=2+$\sqrt{3}$，y=$\frac{1}{2-\sqrt{3}}$，则x与y关系是（　　）

依次填入下面一段文字横线处的句子，衔接最恰当的一项是(　　)
音乐是流动的艺术，音乐的发展也是连续的。         。         ，         ，         。         ，到那时，现代音乐也将以一种主流音乐为方向！
①整个西方音乐在21世纪将以一种崭新的姿态向前迈进
②然而在19世纪末至20世纪初那场音乐革命的推动下
③多元化、一体化现象必将越来越多
④从出现到繁荣，再到消失，音乐也遵循着事物发展的必然规律
⑤不过有一点世界终将以一种符合全球的文化为主流

    There are times when people are so tired that they fall asleep almost anywhere.We can see there is a lot of sleeping on the bus or train on the1home from work in the evenings.A man will be2the newspaper,and seconds later it3as if he is trying to4it.Or he will fall asleep on the shoulder of the stranger5next to him.6place where unplanned short sleep7is in the lecture hall where a student will start snoring（打鼾）so 8that the professor has to ask another student to9the sleeper awake.A more embarrassing（尴尬）situation occurs when a student starts falling into sleep and the10of the head pushes the arm off the11,and the movement carries the 12of the body along.The student wakes up on the floor with no13of getting there.The worst time to fall asleep is when14.Police reports are full of15that occur when people fall into sleep and go16the road.If the drivers are 17,they are not seriously hurt.One woman's car,18,went into the river.She woke up in four feet of19and thought it was raining.When people are really20nothing will stop them from falling asleep—no matter where they

are.