John is the only one of the students in our class that never ________a mistake even when it is pointed out to him.
—I paid him 200 yuan for the sneakers.—Oh, he charged you too much. You _________ them with half the money.
The comments which he made _________ marketing bothered his boss greatly.
You must trust him; he is a man who _________ his promise.
There is such a problem _________ we all should _________.
In the competition to be held, a gold medal, together with a certain sum of money, _________ the champion.