however /but/yet/

　　although/though; while/whereas; in spite of ;no matter how; whether...or...

　　even if/even though/even when

　　on the contrary; rather than; on the other hand ;unlike(转折和让步---对比关系)

　　becasue/as; so/therefore/thereby/thus/consequently; lead to/result from ; because of/due to/owing to/on account of(因果)

　　in fact/in effect/furthermore/moreover/in addition/besides ; still/ also; indeed/furthermore(递进)

　　so that/so...that...(目的和结果)

　　and/or/as well as(并列)

　　which/than/that(关系词)

　　if/providing/supposing; until/unless; as if/if only/lest; in case

　　since/now that

　　what/who/whom

　　likewise ; forever ; other than ; but for

　　补充：作为正确答案的高选频词汇

　　Convert, reverse, respond, ignore, consume, identify, expect, maintain, increase, decrease…(动词)

　　Substantially, significantly; incidentally, approximately; irregularly; exceedingly…; far/even/much加强比较级(副词)

　　Extensive; excessive; significant; reverse, particular; vulnerable/susceptible; available; identifiable…(形容词)

　　Without; against; on; beyond; for(介词)