Ⅰ.阅读理解(共15小题；每小题2分，满分30分)
A
Worldfamous violinist Itzhak Perlman was stricken with polio as a child.As a result，he wears braces on both legs and walks with the aid of crutches.At_concerts，getting_on_stage_is_no_small_achievement_for_him.He slowly crosses the stage until he reaches his chair.He lays his crutches on the floor，slowly undoes the clasps (扣环)on his legs，puts one foot backward and extends the other one forward.Then he bends down and picks up the violin，puts it under his chin(下巴)，nods to the conductor，and starts to play.
