“4＜k＜6”是“方程$\frac{x^2}{6-k}+\frac{y^2}{k-4}=1$表示椭圆”的（　　）

1. 20枚这样的硬币约厚（ ____ ）厘米，30枚约厚（____  ）厘米。
   
2. 

The Special Olympics

    The Olympics are some of the most exciting sports events in the world. But there is another Olympics about which you may not have heard. This is the Special Olympics, for people with mental disabilities.

    The first Special Olympic Games were held in Chicago in 1968. One thousand people competed in many events. Since then Special Olympic programs have been organized in all 50 states and more than 150 countries. Today more than a million people take part in the Special Olympics.

    Mentally disabled persons over the age of eight may take part in the Special Olympics. These people may also have physical disabilities. People have run in races using crutches or walkers. A young girl enter the long jump event with an artificial leg. A blind runner raced around the track with the help of his coach's voice. A deaf basketball team planned their plays using sign language.

    Winning is wonderful for people who may never have had much success. But training for and entering the Special Olympics is also important. The participants become more confident. They learn how to concentrate in order to play well. Then they use that concentration in school to improve their schoolwork. Like anyone else they feel great when they prove they can do something well.