用过去式来描述现在和未来

tense – n. a form of a verb that is used to show when an action happened

phrase – n. a group of two or more words that express a single idea but do not usually form a complete sentence

uncertainty – n. he quality or state of being doubtful or unknown

casual – adj. suited for ordinary use when you are relaxing; not suited for serious or official speech and writing

drop off – phrasal verb. to take something or a someone to a place and then leave

rude – adj. not having or showing concern or respect for the rights and feelings of other people

assume – v. to think that something is true or probably true without knowing that it is true

hypothetical – n. not real: imagined as an example