It’s a difficult skill to master, but ______, it will benefit you for the rest of your life.
Our school had about 20 notebook computers but only one-forth_____used regularly. Now we have 50 working all day long.
I can’t say which wine is best, it’s a(n)___ of personal taste.
It was in the lab___was taken charge of by our teacher____ they did the experiment.
Our teacher makes good use of any time______ he can spare.
London,______ last year, is a nice old city.