flare up突然烧起来/突然发怒
flash out突然说/突然表现出来
fly into a temper大发脾气勃然大怒
focus...on使眼睛注视/集中
follow out贯彻/把…探究到底
follow through坚持到底
follow up穷追(猎物等)
for ages长期
for certain肯定地/确凿地
for ever永远
for example例如
for fear of由于害怕/生怕/以免
for good永久地/一劳永逸地
for instance例如/比如/举例说
for lack of因缺乏/因没有
for life终身
for sale待售/出售的
for sure确实/毫无疑问地
for the best(完全)出于好意
for the better好转/向好的方向发展
for the future从今以后/在今后
for the moment暂时/目前
for the present目前/暂时/暂且
for the rest至于其余/至于其它
for the sake of为了/为了…的利益
for the time being暂时/眼下
for what it is worth不论真假
forget about忘记
free and easy不拘形式的/随便的
free from不受…影响的
free of无…的/摆脱了…的
freeze up(使)冻结
from memory凭记忆
from now on今后/从现在起
from time to time时常/有时/不时
