The National Association for Sport and Physical Education says twenty to thirty students in a P.E.class should be the limit.

VOA: special.2009.08.06

I've been teaching this stuff for twenty years, and I tend to find two basic kinds of students who shop my classes for the New Testament Introduction course.

这门课我上了20年，发现所有参加新约导论的学生,大致可归为两类。

耶鲁公开课 - 新约课程节选

The number of Japanese students in the United States decreased for the fourth year, to just over twenty-nine thousand.

VOA: special.2009.11.26

That was when twenty-five students in a class taught by Thomas Zurbuchen first talked about the idea.

VOA: special.2009.02.16

Last year,more than six hundred twenty thousand, or three and a half percent, were international students.

VOA: special.2009.02.05

But alcohol is banned in first-year dorms -- where most students are under twenty-one anyway.

VOA: special.2009.04.02

And college women twenty-one to twenty-three had bigger increases than non-students in that age group.

VOA: special.2009.08.07

Earlier this year they tested them with five hundred students in twenty classes.

VOA: special.2009.09.03

Twenty-six thousand foreign exchange students are in American high schools this year.

VOA: special.2009.11.05

It has more than four thousand students, including twenty-six international students currently.

VOA: special.2009.03.05

About two thousand volunteers help students in twenty-three cities across the country.

VOA: special.2010.07.16

about twenty percent of all the international students in the world.

VOA: special.2009.02.05

But Dennis Jin disagrees: For high school students in China, we must reach class at six-twenty in the morning and be back home sually at ten in the evening.

VOA: special.2010.10.14

Students were not considered adults until twenty-one.

VOA: special.2009.07.09

The students were ages eighteen to twenty-five.

VOA: special.2009.03.12

(Sound) Twenty years ago, thousands of students braved riot police in Prague, demanding an end to decades of communist rule in what was then Czechoslovakia.

VOA: standard.2009.11.17