1 successfully producing the result that you want 有效的:
a medicine that is effective against the common cold能治好一般感冒的药物That picture would look more effective on a dark background.那幅画要是用暗色的背景衬托,效果会更佳。 [OPP] ineffective 反义词为 ineffective
2 real or actual, although perhaps not official 真正的,实际上的(也许不是正式的):
The soldiers gained effective control of the town.军队已取得该镇的实际控制权。 ➔effectivenessnoun [U]
effective/əˋfɛktIv; IˈfektIv/adj 1 having the result that you want [ ineffective ] 有效的﹔产生预期效果的: an effective way to teach reading 一种教授阅读的有效方法a highly effective method 一种非常有效的方法2 [not before noun 不用于名词前] if a law, agreement, or system becomes effective, it officially starts〔法律﹑协议或制度〕生效的: +from The new regulations are effective from April 5th. 新规则从 4 月 5 日起生效。—effectiveness n [U] COST EFFECTIVE