____ gets well prepared will pass the exam easily.
He made up his mind to devote his life ______ the river ______ polluted.
---Are you firmly against any independence move by Taiwan? ---Of course. That’s ______ our basic interest lies.
______ on a true story, the film is well worth ______ .
Mr. Johnson ______ his boss ______ his careless mistake.
---What do you think made Celia so happy? --- ______ a prize in the recent competition.