题目

One fine afternoon I was walking along the Fifth Avenue, when I remembered that it was necessary to buy a pair of socks．I   1   the first sock shop that caught my eye, and   2  , not more than 17, came forward. “What can I do for you, sir?” “I wish to  3   a pair of socks．”   4   glowed. “Did you know that you had come into   5   in the world to buy socks?” I had not been   6   that, as my entrance had been accidental．“Come with me,” said the boy happily．He began to   7   down from the shelves box after box． “  8 , boy, I’m going to buy 一棵大树在一次强台风中于离地面5米处折断倒下，倒下部分与地面成30°夹角，这棵大树在折断前的高度为（     ）。