-----Do you know where David is ?  I couldn’t find him anywhere.-----Well. He _______have gone far-----his coat’s still here.

Facts prove that the world’s economic development is not a win-lose game but one in which all _____ be winners.

Tom, you ____ leave all your clothes on the floor like this.

— My sons are not a little restless.— Oh? Boys _______ be boys．

If you ___ stick to the unrealistic approach, the worse result will be waiting for you not far ahead.