a very thin sheet of metal, especially used to wrap food in to keep it fresh

tin foil 锡箔

UK aluminium foil 铝箔

something or someone that makes another's good or bad qualities more noticeable

The older, cynical character in the play is the perfect foil for the innocent William. 剧中年迈、愤世嫉俗的人物角色正好衬托出威廉的天真单纯。

a thin, light sword used in the sport of fencing

to prevent someone or something from being successful

The prisoners' attempt to escape was foiled at the last minute when police received a tip-off. 由于警方收到密报，囚犯的越狱企图在最后一刻被挫败。