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.
The policemen searched the room thoroughly. That’s to say, they searched it ______.
She had _______ got out of the house _______ it began to rain.
In December 2008, Obama was _________________.
Sometimes children are _______ enough to create ______ stories.
The professor _______ to walk out of the office when one of his students came in.