I’m sorry I delayed_________ your letter because I have been quite busy these days.

It is a long time _____I saw you last——YesAnd it will be a longtime _____ we see each other again

Europe has achieved more in controlling the AIDS virus than Asia in the past ten years, ______ the number of people infected with the virus is going up sharply [ ]

Why are you staring at me—You look stupid! The way you wear is _______ annoys othersmost

rks, ________ of gun powder or flashpowder _______ in a tight paper tube, make the big flash or boom effect.