I saw your son ____ football on the playground when I called you yesterday.A. to play B. played C. playing
I’d like to have a word _____________ Tony. A. on B. with C. in
_____ the environment is important for human beings.
I can’t stand _____ for you so long.
—Is the bag beautiful?—Yes, at _____ it’s _____ the one you bought for me.
Our teacher told us that light _____ much faster than sound.