The little boy ________ his seat to an old lady on the crowded bus.
—I don’t know _______ now. —She is much better today.
_______ they are twin brothers, they don’t look like each other.
—Do you mind if I smoke here? —_______ You can go to smoke in the next door.
Sandy didn’t tell her parents that she was going home because she wanted to give them a _______.
This is _______ difficult problem that few students can work it out.