Between the two periods of classes is a break, _______ we can have a short rest.
The students _______ busily when Miss Brown went to get a book she _______ in the office.
I think you must be mistaken about seeing him at the theatre; I’m sure he ____abroad all week.
They haven’t arrived yet but we _____ them at any moment.
I feel sure I _____ her before somewhere.
You’ll never guess who I met today — my old teacher! We _____ for 20 years.