Zu Chongzhi was one of the     1     （great）mathematicians（数学家）in ancient China. He was born during the Northern and Southern dynasties. From a young age, Zu was taught natural science, astronomy（天文学）, math and so on. The little boy     2     （show）interest in all of these subjects, especially in math.

Zu was best known     3     his calculation（计算）of pi（π）. According to the record, he did all the work using nothing but wooden sticks. He spent lots of time     4     （work）out the value between 3. 1415926 and 3. 1415927. No one at that time was able to do better than Zu. And now the     5     （achieve）is still praised by people around the world. In order     6     （remember） Zu, some mathematicians suggest calling pi “Zu Lv”.

Zu made great achievements not only in math,     7     also in astronomy. He worked out that a year should be 365.24281481 days long and created the Daming Calendar. However, government officials at that time did not agree with Zu. The great mathematician never saw     8     （he）calendar put into use. Almost ten years after his     9     （die）, the new calendar was accepted.

Zu was     10     inventor, too. He once made a vehicle（车辆）which carried a pointer（指针）. No matter how the vehicle turned, the pointer always pointed to the south.

Bill Gates was known as the founder of Microsoft company. Bill Gates was     1    on Oct. 28th, 1955. He grew up in Seattle, Washington. He was     2     very clever boy. His favorite subjects at school were science and math.     3     he was 13 years old, Bill started to play with computers. At that time, computers     4     very large machines. Once he was very interested     5     a very old computer. He and some of his friends     6     lots of time doing unusual things with it. In the end, they worked out a software program（软件程序）with the old machine. Bill     7     it for 4, 200 dollars when he was only 17.

In 1973, Bill entered Harvard University. In the third year, he left Harvard to work for a programming company. Bill began his company in 1975     8     his friend Paul Allen. They thought the computer would come into every office and every home soon. So they began developing the software or personal     9    . They improved the software to make it     10     for people to use computers.