effective是有效的,起作用的意思,用于事物或人,一般是呈现出正确的结果或是解决了问题。例句:
The government took effective measures to reduce the price.政府采取了有效措施来降低物价。
efficiency
n.效率;效能;功效
The workers in this factory are working without morale and the efficiency is of course low.这家工厂的工人干起活来毫无士气,效率当然也很低。