21.   A person did.

22.   A witness thinks a person did it.

23.   A. I distrusted myself, as a person wisely should do.

24.   All the rules of law are built around assumptions about what a reasonable person would do, Ms. Charo said.

25.   But no one is able to understand why another person does something.

26.   But the best thing a person can do with a computer is give it away.

27.   But the findings were especially surprising because, as a rule, doctors have much better access to health care than the average person does.

28.   But what this person did is wrong.

29.   By examining these times for every file on the computer, an investigator can create a very detailed picture of what a person did.

30.   By saying that this person is doing a good job, you are probably referring to her technical skills and general ability to complete her work.