Could you please ________ such a thing again?
Mr Chen __________ his mobile phone to the shop because it can’t work at all.
Computers have made a great difference _______ our everyday life.
After half a day’s hard work, we made our classroom look as _______ as new.
_______ provides many hours of air for astronauts in space.
We are wondering ________ we can prevent people from polluting the earth.