. He _____ his potential had it not been for his desire to meet new challenges.
28. The officer was very concerned ________ the latest development in the case because he was concerned ________ it.
27. If we ________ to him, he will make further demands.
26. Parents always tell us not to stay ________ there is danger.
25. – Tom, it's too late. Our son ________ be back. – Don't be anxious. I dare say he ________ have some extra work to do.
24. More than one ________ the people heart and soul.