一般现在时：
1.Bamboo can be made into fine paper.
2. Knives are used for cutting things.
3. English is spoken in many countries.
4. The book is written by Ba Jin.
5. The classroom is cleaned everyday.
一般过去时：
1. The thief was caught yesterday.
2. The bridge was built last year.
3. Those kids were brought here by their parents.
4. I was praised yesterday by my teacher.
5. It was published in 1990.