.in fear of (=afraid for the safety of)擔心
.feed (sb.) on sth. 靠吃……，用……喂養(yǎng)
.be fed up with (=be unhappy, tired about sth. dull)厭煩，膩了
.feel like (=have a desire for)想要
.fill in填寫
.fill out (=fill in)填寫
.set the world on fire = set the flames on fire (=do sth. remarkable)有突出成就
.play with fire (=take great risks)干冒險事
.set sth. on fire (=set fire to sth.)使……著火，放火
.at first sight (=when first seen)乍一看，一見
.for the first time第一次(作狀語)
.in the first place首先，第一
.fit into剛好放入