He started to learn English in 1990 and in the years ________ he kept on using it in his work.
Go on ________ the other exercise after you have finished this one.
She reached the top of the hill and stopped ________ on a big rock by the side of the path.
In some parts of London, missing a bus means ________ for another hour.
—The light in the office is still on. —Oh,I forgot ________.
—You were brave enough to raise objection at the meeting. —Well, now I regret ________ that.