2. Five times zero equals ______.

A. five　　　　　　　　　 B. ten　　　　　　　　　 C. fifty　　　　　　　　　　 D. zero

1. The system of numbers that nearly everyone use today ______ the numbers from 1 to 9 and 0.

A. are　　　　　　　　　 B. consist of 　　　 C. is　　　　　　　　　　　　 D. consists of

5. She is at _____ 50 years old.(little)

4. The abacus is one of the first ______ machine which is fast and accurate.(calaulate)

3. Do you think the brain is a _____ computer?(live)

2. Edison ______ many things in his lifetime. All his ______ were very important .(invent)

1. China is a _____ country.(develop)

5. 13 is an______(odd, even)number.

4. He was ______(amusing, amused)to hear the news.

3. The ______(live, living)are important to us .