Idioms are used all the time and unless you recognize when an idiom is being used, what you read or hear ______ can easily be misunderstood
Professor Liu has ________ teach psychology since he came to the Central China Normal University.
----Any news about Bill Clinton? ----He left power three years ago and has a little now and a little then been ______.
If you want to sell your product you must _____ it.
—Shall I open the window to let some fresh air in?. —No, ______.
Someone called me up in the middle of the night, but they hung up ______ I could answer the phone.