Thomas _____ a soldier, for he is much too short.

If you ________ smoke in the room, please keep the windows open.

 -- There were already five people in the taxi, but the driver managed to take me as well.  --It ________ a comfortable journey.

The doctors are doing all that they _____, but the old man is still not breathing properly.

 —I’ll call Bob and tell him the good news.—You __________ do that. He was here just now and heard it.