1) but表示转折，while表示对比。 Some people love cats, while others hate them. 典型例题 --- Would you like to come to dinner tonight? --- I’d like to, ___ I’m too busy.http://yingyu.chazidian.com A. and B. so C. as D. but 答案D。but与前面形成转折，符合语意。而表并列的and， 结果的so，原因的as都不符合句意。 2) not…but… 意思为不是……而是…… not 和but 后面的用词要遵循一致原则。 They were not the bones of an animal, but (the bones) of a human being.