certify certificate 区别

certify certificate 区别
作为动词时,请问 certify 和certificate 在意义上有什么具体的区别?

据《牛津高阶英汉双解词典》：
certificate（动词） ：1、an official document proving that you have completed a course of study or passed an exam; a qualification obtained after a course of study or an exam.颁发结业证书.
2、 an official document that may be used to prove that the facts it states are true.证明、证明书.
certify（动词）：1、[usually passive]to give sb an official document proving that they are qualified to work in a particular profession.(通常用于被动语态）颁发或授予专业合格证书.2、 to state officially,especially in writing,that sth is true.证明、证明书.
就证明而言,二者同义.就颁发证书而言,某人有资格有能力从事某项职业时才能用certify.而如果他只是完成了学习或培训任务,就只能用certificate .
certificate 也可用作名词,表示文凭、结业证书.