阅读理解

　　　Mr and Mrs Smith had always spent their summer holidays in New Jersey in the past, staying in a small inn (旅店) at the foot of a hill.

One year, however, Mr Smith made a lot of money in his business, so they decided to go to London and stay at a really good hotel while they went touring around that famous city.

　　　They flew to London and arrived at their hotel late one evening. They had expected that they would have to go to bed hungrily, because in that small inn in New Jersey, no meals were served after seven. They were surprised when the waiter asked whether they would take dinner there that night. “Are you still serving dinner？” asked Mr Smith. “Yes, certainly, sir，” answered the waiter, “we serve it until half past nine.”

　　　“What are the times of meals then？” asked Mr Smith. “Well, sir，” answered the waiter，“we serve breakfast from seven to half past eleven in the morning, lunch from twelve to three in the afternoon, tea from four to five, and dinner from six to half past nine.”

　　　“But that hardly leaves any time for us to see the sights of London，” said Mr Smith.

$\sqrt{\left(3-a\right)\left(a+6\right)}$（﹣6≤a≤3）的最大值为（　　）

读课文《悼念玛丽•居里》，全文的中心论点是____。

      Ruby, the artist, is an Asian elephant, She is17 years old. She lives in the zoo. Ruby has produced about 100 paintings since last year. She has made more than $ 40,000 for the zoo. Zoo leaders say Ruby first showed the talent (才能) about four years ago. Zoo workers watched her make the marks in the sand with her trunk. She rubbed (擦掉) out the marks, then made the new ones. The zoo worker gave her brushes and paints. Soon Ruby painted pictures.
       Newspaper reporters wrote Ruby, then people asked about buying her pictures. And in this way, she made a lot of money for the zoo. This is how Ruby does the paintings. A zoo worker holds different color paints. Ruby touches the colors she wants. Then the worker gives her brushes with the chosen colors in her trunk and Ruby begins painting.