I was standing behind a tall man．When the man looked _____, I recognized him at once．

  Four teams of three people would compete ______ the game and the winners would receive a free vacation.

My son prefers us to email each other once a week       spend half an hour on the phone every night.

Look at this year's sales figures ________ last year's; they're so much better.

Britain, ______________many other industrialized countries, ______ experienced major changes over the past 100 years.