The time he has devoted in the past years __________ the disabled is now considered to be__________ great value __________ him.
While she _____ TV, someone _______ at the door.
---Can you tell me __________? ---Yes. She came here on foot.
The news made me ________.
----How are you going, buddy? ----________. A little busy, though.
Scientists from different countries are trying to_______ a good way to solve the energy problem.