At most American colleges, undergraduate students choose one area of study, like English or biology, and focus on it for all four years of their education.

VOA: standard.2010.05.12

We have some students who enter on an athletic team and stay all four years with that team.

有些学生是因为体育特长,而被录取，而且大学四年,仍然从事那项体育活动。

普林斯顿公开课 - 人性课程节选

Forty-four point four percent of all children between the ages of ten and seventeen years were obese or overweight.

VOA: special.2009.07.21

World leaders agreed this week to protect all nuclear materials within four years to stop the possibility of nuclear terrorism.

VOA: special.2010.04.17

It was responsible for more than four and one-half percent of all the years people lived with disability.

VOA: special.2009.09.08

All the men were tested for sexually passed diseases four times in the next two years.

VOA: special.2009.04.01

And,all of the students were required to study for four years instead of three.

VOA: special.2010.06.27

But four years ago this month a jury cleared him of all charges.

VOA: special.2009.06.27

For more than four hundred years, people all over the world have been reading,watching and listening to the plays and poetry of the British writer William Shakespeare.

VOA: special.2010.01.06

And so you are really good friends with like all the people you're in class with, because you know them since like four years and you have all classes together with them."

VOA: special.2009.11.05

"I am announcing a new international effort to secure all vulnerable nuclear material around the world within four years."

VOA: standard.2010.04.06

In the next four years, it plans to provide all its citizens with a national identity number.

VOA: standard.2009.09.24

It all began three or four years ago when there was construction boom.

VOA: standard.2010.06.24

Tens of thousands of Scouts from all 50 states and 26 other countries come to the United States every four years for 10 days of adventure and fun.

VOA: standard.2010.07.31

we're going to lean on each other.' And that's what we've done here the last four years and this is the culmination of all that belief and that faith."

VOA: standard.2010.02.08