11. When taken _______ excessive amounts, aspirin can be poisonous. A. of B. with C. in D. at 12. _____ gold is ___ excellent conductor of ______ electricity. A. θ/an/ θ B. θ/an/ the C. A/the/the D. θ /the/ θ 13. Not until ________ did I recognize him. A. after B. before C. latter D. following 14. My brother has _________ in the military. A. joined B. entered C. served D. participated 15. Having no way to refuse, she followed him to the campfire of their host. What is the opposite meaning of the underline word? A. choose B. promise C. deny D. accept 16. After one-month stay with his aunt in the countryside, Linh was accustomed _______ farm life. A. on B. at C. with D. to 17. The cars needs _________ before you can use it again. A. repairing B. be repaired C. to repair D. repaired 18. I made a lot of noise when I came home. You _______ me A. must hear B. must have heard C. have to hear D. had to hear 19. You are only one _______ many who need help A. among B. between C. around D. besides 20. Crop circles, small areas of crops in ___________ patterns, are a modern-day mystery. A. elaborately swirling B. elaborately swirled C. elaborate swirling D. elaborate swirled