56. changed → changing
57. which → in which (where)
58. too → either
59. limit → limited
60. grown → grew
61. 去掉 an
62. 正确
63. name → names
64. new → of new
65. introduced → were introduced 的

Dear schoolmates,

　　First of all, let's give our warmest welcome to our honourable guest --- Mr Luois Alexander. Mr Luois Alexander is a world-famous English linguist. He's written lots of works, including New Concept English, Follow Me and so on. All these are well known to us all. Mr Alexander is invited to Chongqing to give lectures, and today he's going to have a talk with us to get a further understanding of English study in middle schools in China. If you have any questions on English, you are free to ask him for help. Now let's invited Mr Alexander to give us a talk and advice on English study. That's all. Thank you