Let's learn to use the problem we are facinga stepping-stone to future success.
Rainforests ____ and burned at such a speed that they will disappear from the earth in the near future.
—Peter, hurry up! You ______ on the phone.—Oh, I ______. Thank you.
I can’t leave the office now. A lot of work ________ to be done.
This book _____ ten units, ______ three mainly revision.
When his mother came in, the boy pretended ______.