什么是短语表达？

phrasal – adj. grammar: of, relating to, or consisting of a phrase or phrases

unit -- n. a single thing, person, or group that is a part of something larger

expletive – n. a word or phrase that fills out (or takes a slot) in a sentence without adding to the meaning

conversation – n. a talk involving two people or a small group of people

practice – v. to do something again and again in order to become better at it