Once __________sport has become less popular, it has to make __________way for new sport which are more popular to enter into the Olympics.
Once out of the earth’s gravity, the astronaut is by the problem of weightlessness.
The doctor telephoned to say that he couldn’t ____ the meeting because he had to ___ a patient.
When we are in a new place, we must __our manners and try to follow the customs of the place.
In the early morning all of us stood at the top of the mountain __ east of the city, watching _____burning sun rising.
The boy was led ___while crossing the road.