Mr Liu is ____ unusual teacher. He has written _____ useful book for his students.
—Which sweater can you choose, the blue one or the red one? —____ is OK, I think. Both go well with my trousers.
Many more trees should ____ this year.
—____ the workers are very tired, ____they keep on working. — They are great. We must learn from them.
If Tony_____ to the corner this weekend, Bob will join him.
Her husband is a great cook. So she can enjoy _____ food every day.