Farm vehicles should be kept out of areas with weeds.

VOA: special.2009.05.26

If you wish to change sections, you may do so only with permission of the subject administrators because it's very important that those sections be kept at a small population.

如果你们想要改时间，你只能在课程管理主任允许,的情况下这样做,因为让课程的人数保持在比较少的水平,是很重要的。

麻省理工公开课 - 固态化学导论课程节选

There's no known cure for hepatitis B, although the virus can be kept in check with anti-viral medicines.

VOA: standard.2010.07.26

Dr.Kallio agrees with Dr.LaVan that the results support the recommendation that kids be kept away from tobacco smoke.

VOA: standard.2010.03.04

"We also feel that former child soldiers should be given assistance and be quickly reunited with their families rather than kept in detention."

VOA: standard.2009.09.16