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.
His hard work paid ____ when he got the result.
. Seeing your picture, I could not resist _____ the days _____ we spent together.
He was _________down for several days after he heard the bad news .
. _______news came ________an unknown disease was spreading in the area .
Your composition is _________to your brother’s.