On Christmas Eve, we put up some balloons to ______ the festival atmosphere.

In the last twenty years, seven Canadian scientists _____ the Nobel prize!

The question that puzzled them is ____ they can get rid of the air pollution in the area.

Helen ________ her keys in the office so she had to wait until her husband ______ home

11. Mrs. White found her husband surroundedby letters and papers and _________ very worried