Hxen.com's tips：Every day persisted can learn English well!-->■Learn English Everyday■
discourse – n. the use of words to exchange thoughts and ideas
conversation – n. an informal talk between two people or a small group of people
informal – adj. relaxed in tone : not suited for serious or official speech and writing
o'clock – n. according to the clock
flexible – adj. able to change or to do different things
assure – v. to make something certain
introduce – v. to present something for discussion or consideration
