On Nov. 18, 1995, Itzhak Perlman, the violinist, came on stage to give a concert at Avery Fisher Hall at 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 two crutches (双拐)．
He walks painfully, yet majestically, until he reaches his chair．Then he sits down，slowly, puts his crutches on the floor, undoes the clasps on his legs，tucks one foot back and extends the other foot forward．Then he bends down and picks up the violin, puts it under his chin，nods to the conductor and proceeds to play．
But this time，something went wrong．Just as he finished the first few bars (小节)，one of the strings on his violin broke. You could hear it snap (嘣断) --- it went off like gunfire across the room. There was no mistaking what that meant. There was no mistaking what he had to do．
We figured that he would have to get up, put on the clasps again, pick up the crutches and limp his way off stage-to either find another violin or else find another string for this one．But he didn’t. Instead, he waited a moment，closed his eyes and then signaled the conductor to begin again．
The orchestra began, and he played from where he had left off. And he played with such passion and such power and such purity as they had never heard before．
When he finished, there was an awesome silence in the room. And then people rose and cheered．He smiled，wiped the sweat from this brow, raised his bow to quit us，and then he said in a quiet tone．“You know, sometimes it is the artist’s task to find out how much music you can still make with what you have left.’’
21．By saying “getting on stage is no small achievement for him”, the author really means .
A．it’s very difficult for Itzhak Perlman to play the violin with three strings
B．it’s not easy for Itzhak Perlman to get on the stage because he is disabled
C．it’s not easy for ltzhak Perlman to face such a large audience
D．it’s really great achievements for ltzhak Perlman to play the violin with three strings
22．Itzhak Perlman when one of the strings of the violin broke．
A．gave up playing
B．didn’t know what to do
C．went on playing the same piece of music
D．went on playing a different piece of music
23．Itzhak Perlman can be best described as a man who is ．
A．clever B．strong willed C．humorous D．quite skilled