In our class, when the bell rang and the teacher closed his book, it was a _______ for everyone to stand up.

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 questionnaire takes _______ ten to fifteen minutes to complete and can be used along with the assessment interview.

You'd sound a lot more polite if you make a request _______ a question.

His efforts to raise money for his program were _______ because no one showed any intention to take a cent out of their pockets.

May open the window to let in some fresh air?"_______"

He told us whether _______ a picnic was still under discussion.

I like this house with beautiful garden in front, but I don't have enough money to buy _______.

Ladies and gentlemen. Please remain _______ until the plane has come to a complete stop.

Have you _______?"No. had the wrong number."