It was not until this year _____ scientists managed to make a cat and a goldfish disappear from sight using an invisibility cloak(斗篷)
He said he would keep________the school rules and keep________smoking.
One of the advantages of living on top floor of a high rise is that you can get a good________.
In the meantime, the question facing business is whether such research is________the costs.
________some of this juice—perhaps you'll like it.
—Write to me when you get home. —________.