8. A: I didn't think Paul and Sam were coming to the picnic.
B: They_____ their minds.
A: Well, it's nice to see them again.
A. must have changed
B. used to change
C. would rather change
D. should have changed
9. I'm glad that I_____ hard to persuade my parents because they were already keen on the idea.
A. ought not to try
B. needn't have tried
C. didn't need to try
D. wasn't able to try
10. When it was completed, the Eiffel Tower______ the tallest building in the world, but now there are many others which are taller than the Eiffel Tower.
A. would be
B. must be
C. used to be
D. was
11. Cats are very alert to any movement. For this reason, they will pounce when a victim _____but _____prey that remains still.
A. can move - couldn't attack
B. is moving - shouldn't attack
C.moves - may not attack
D. moved - don't attack