题目

第三部分  阅读理解（共20小题，；每小题2分，满分40分）      On Nov.18, 1995, Itzhak Perlman, the violinist, came on stage to give a concert in the Avery Fisher Hall at the Lincoln Center in New York City.      If you have ever been to a Perlman concert, you know that getting on stage is no small achievement for him.  He was stricken with polio (小儿麻痹症) as a child, and so he has braces (支架) on both legs and walks with the aid of a pair of crutches (拐杖).      He walks painfully until he reaches his chair.  Then he sits down  slowly,  puts h地球是我们人类赖以生存的“家园”，而大气层是这个“家园”的保护伞．著名的________实验有力的证明了大气压的存在，________实验最早测出了大气压的值．人们把________毫米高的汞柱所产生的压强称为1个标准大气压．