日期：
来源：雅诚德英语网
The skin samples were collected from 2007 to 2009 with a stainless steel dart.
皮肤样品是自2007年至2009年间用不锈钢标枪收集到的。
The skin samples were collected from 2007 to 2009 with a stainless steel dart.
皮肤样品是自2007年至2009年间用不锈钢标枪收集到的。