You can only be sure of_________ you have at present; you cannot be sure of something _____ you might get in the future.
_____ as the most excellent student in her university, as most classmates had expected, made her parents very happy.
At no time does the salesgirl get up late in the morning, for she is always too busy _____ a good rest.
It was _____ computer games that cost the boy a lot of time that he ought to have spent on his lessons.
_____ he’s only been learning English for a year, he speaks it very well.
--- I hear Warren _____ in a middle school. --- What? I can’t imagine him _____ as a teacher.