原

• It is its being so old and grey, perhaps .
  也许因为它太老太灰暗的原故吧。
• Other agents can cause similar syndromes .
  其它病原也可引起相似的综合症。
• It has leaf primordia and a shoot apex .
  它有叶原基和一个苗端。
• Prototrophs can grow without added factors .
  不加生长因素原养型也能生长。
• They should not have been allowed to come .
  原不该让他们来的。
• He was a former electronics engineer .
  他是一位原电子工程师。
• The protoplanets were huge affairs .
  原行星是一个巨大的天体。
• He was recalled to the original department .
  他被调回原部门。
• He was a studious gentle lad .
  他原是个好学的，温顺的孩子。
• Enterokinase acts on trypsinogen .
  肠致活酶作用于蛋白酶原。