It was some time _______ I realized the truth.
When _____ different cultures, we often pay attention only to the differences without noticing the similarities.
Hundreds of species are declared to _____ in the coming century.
It was playing computer games ____ cost the boy plenty of time ____ he ought to have spent doing his lessons.
We _____ live in a small flat but last year we bought a house.
All these gifts must be mailed immediately_________ in time for Christmas.