11.   A few schools like Penn State have real students.

12.   A professor of dendrochronology has students slicing up wood samples from trees and from the beams of medieval buildings from the eastern Mediterranean.

13.   A school district may have a high rate of disciplinary incidents because it has very strict rules and not necessarily because it has unruly students.

14.   But already, Ms. Vojdik said, having four students is far better than one.

15.   But a leading opponent of affirmative action in higher education said the poll merely showed the value of having students with a variety of viewpoints and backgrounds.

16.   But Edwin Walker, superintendent of the North Forest public schools, says every school has students in this situation.

17.   But if one goal of having older students on campus is allowing younger ones to get to know them, that has not been easy to achieve.

18.   But the hardest part, he said, is having no students.

19.   But the New York Civil Liberties Union objected strongly to the proposal, noting that the New York City school system has many students who are not American citizens.

20.   But the university said it had no student by that name, and Palestinians in Nablus said no such person had been traced in the city.