11. What's the _______ between peanut butter and jam? * A. difference B. different C. differently 12. This new programme will _______ older people to study at university. * A. able B. ability C. enable 13. He completed the task with the _______ of his personal secretary. * A. assist B. assistant C. assistance 14. There is a great _______ of houses in most big cities. * A. short B. shorten C. shortly D. shortage 15. Although Ken was a good shooter, he _______ missed the target. * A. repeat B. repetition C. repeated D. repeatedly 16. The film is _______ based on a short story. * A. suppose B. supposition C. supposed D. supposedly