1. We _____ live in a small flat but last year we bought a house.
A. would B. had to C. used to D. ought to
2. It was playing computer games ____ cost the boy plenty of time ____ he ought to have spent doing his lessons.
A. what; that B. that; when C. which; that D. that; that
3. Hundreds of species are declared to _____ in the coming century.
A. die away B. die out C. die down D. die off
4. When _____ different cultures, we often pay attention only to the differences without noticing the similarities.
A. compared B. being compared C. comparing D. having compared
