—You were out when I dropped in at your house.—Oh, I_______ for a friend from England at the airport.
I like to listen to music ______ I’m having a walk in the evening.
______ the terrible pollution, so many beautiful fish are fast disappearing in the river.
All of us found ______ difficult to work out the maths problem.
Doyouhappentoknow________?
Let Tom play with your toys as well, Clare—you must learn to_______.