· flaky
· He is too flaky to do the work.
· MEANING: unreliable (来源：英语学习门户网站EnglishCN.com)

· flashback
· At the wedding he had a flashback of his old girlfriend.
· MEANING: remembered

· flick
· I haven't seen a flick in a long time.
· MEANING: movie (来源：英语交友 http://friends.englishcn.com)

· flip out
· He flipped out when he heard that his mother had been killed.
· MEANING: lost control

(来源：专业英语学习网站 http://www.EnglishCN.com)

· flip side
· What kind of music do you have on the flip side of the tape?
· MEANING: other side

· fox
· His older sister is a fox.
· MEANING: very attractive (来源：英语问答中心 http://ask.englishcn.com)

· foxy
· She is a foxy lady.
· MEANING: sexy (来源：专业英语学习网站 http://www.EnglishCN.com)

· freebie
· The pillow was a freebie
· MEANING: free (来源：英语分类信息 http://fl.englishcn.com)

· get into something
· I got into gardening in high school.
· MEANING: became seriously interested in

· get it
· I listened to the joke twice, but I still don't get it.
· MEANING: understand (来源：英语论坛 http://bbs.englishcn.com)

· get with it
· If you don't get with it, we will never finish this work.
· MEANING: hurry up (来源：英语分类信息 http://fl.englishcn.com)