由460个碱基组成的DNA分子片段，可因其碱基对组成序列的不同而携带不同的遗传信息，其种类数最多可达（　　）

当今的中国正处于转型期，人们对文明的焦虑和不自信也属正常不过，人们在谴责别人的过错时是否也应该考虑事件的真实性？比如上半年出的“中国游客泰国铲虾” 事件，人们对该事件一再谴责，①____。从某种意义上说，这是文明焦虑上的极端情绪表现，它让人变得目光短浅、妄自菲薄。因此，人们在面对一件事时不能妄下定论，需看清背后的真相。当然，从某种层面也能看出，②____。但人们不应把一件小事无限放大，③____。虽然人人都应争做“国家名片”，但个人行为属个人行为，不应由全国人民“背黑锅”。

化简：$\frac{x^2-9}{x^2+6x+9}$=____ 

    One day, Mr. Black went into a restaurant. He put his coat on a chair near the door. There was nothing in the pockets of his coat. After he had his meal, he went to take his coat back. He found there was much money in one of his pockets. “Whose is this?” he thought. He saw a waiter near the door. So Mr. Black said to him, “Somebody put a lot of money in my coat. I have no time to wait for him. I have to go. Take it, please. When he comes back, give it to him.” The waiter took it and went away. At the moment, another man came with a coat just like Mr. Black's. “I'm sorry,” said the man. “I took your coat and you got mine. Please give me my coat and the money. ” Mr. Black answered, “I gave it to the waiter. He'll give it to you. ”

    Mr. Black called the manager（经理）, but the manager said, “We have no waiters here. We only have waitresses（女服务员）. He must be a thief（小偷）.”