有的跑车在车的尾部设计安装了一种“气流偏导器”，它的上表面平直，底部呈弧形凸起，相当于一个倒置的翅膀，这主要是为了让跑车高速行驶时，车轮能更好地抓紧地面。请解释其中道理。
由于气流偏导器上表面平直，下表面凸起，所以当跑车高速行驶时，流过气流偏导器上方的空气流速较慢，压强较大；而流过下方的空气速度较快，压强较小。这样，偏导器上下方所受的压力差形成了一个向下的力，从而使车能抓紧地面。
| 短文改错。 此题要求改正所给短文中的错误。对标有题号的每一行 作出判断； 如有错误（每行只有一个错误），则按下列情况改正： 此行多一个词：把多余的词用斜线( ＼) 掉，在该行右边横 线上写出该词，并也用斜线划掉。 此行缺一个词：在缺词处加一个漏字符号(^) ，在该行右 边横线上写出该加的词。 此行错一个词：在错的词下划一横线，在该行右边横线上 写出改正后的词。 | |
| One day, Tom and his friends were playing a cat in a room. There is a pretty blue glass on the table. When Tom was trying to catch the cat, he hit a glass and broke it.Tom began to cry. He was afraid of that his father will beat him. John, one of his friend, said,"Never mind, tell your father it was the cat who broke it."But Tom said,"No, no!I will not tell lie."Then he went at once to his father and told him that he had done. His father didn't beat him. Instead, he was so glad that his son had told him the truth． | 1. _____ 2. _____ 3. _____ 4. _____ 5. _____ 6. _____ 7. _____ 8. _____ 9. _____ 10. _____ |