1.合成名词(动词原形+前置词)如setback,outlookhandover, sidewalk, takeover feedback, tabletop, forehead2.合成名词（形容词+名词）bluetooth, blackmail, fastfood, goodwill, backpack, hillside3.合成动词upload, download, tiptoe, foresee, forklift4.合成形容词airsick, seasick, breathtaking, stonecold, heavyduty, overdue。