2012托福 考试:托福写作必备抽象词(十二)
Mechanism
用法：①In a machine or piece of equipment， a mechanism is a part， often consisting of a set of smaller parts， which performs a particular function.
② A mechanism is a special way of getting something done within a particular system.
例句： Plants are subject to attack and infection by a remarkable variety of symbiotic species and have evolved a diverse array of mecha
