If properly managed, clearing and replanting trees in a 30-year cycle creates both a renewable source of energy and maximum rubber production.

VOA: standard.2009.09.13

And so in the 1940s, a group of people led by Collier started to develop a large scale production method for making a reliable source of vaccinia virus.

在二十世纪四十年代,科利尔带领一群人开始研究,一种大规模的生产方法,这种方法能制得牛痘病毒的可靠来源

耶鲁公开课 - 生物医学工程探索课程节选

And so in the 1940s, a group of people led by Collier started to develop a large scale production method for making a reliable source of vaccinia virus.

在二十世纪四十年代,科利尔带领一群人开始研究,一种大规模的生产方法,这种方法能制得牛痘病毒的可靠来源

耶鲁公开课 - 生物医学工程探索课程节选