6. As there is less and less coal and oil, scientists are exploring new ways of making use of   energy, such as sunlight, wind and water for power and fuel.

Professor Wang is a friend of mine who works in a ________ school.

When he heard the _______ news that an earthquake occurred in Sichuan, he felt very___________.

Don’t blame your brother. He had____reasons for not supporting you.

 Only _____ people can have a good understanding of the lecture given by the scientist.