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d a headache. 14. keep sth. Under lock and key 15. brightly colored pills 16. colored / colorful 17. mistake A for B He often mistakes wheat for rice. She is often mistaken for her twin sister. 18. admit admit sth./ admit doing sth. / admit / that…… .. He admitted his mistakes. He admitted having made the mistake. He admitted that he had made the mistake. admit … .. into They have admitted me into their club. He has been admitted into Fudan University. 19. A great / large /good quantity of = great / large / good quantities of = plenty of / a lot of a number of a great deal of / a great amount of a good / great many 20. elderly people : the old The old are living a happy life in