lose efficacy，lose effectiveness，be no longer in force，become invalid，abate ；

[例句] 要记住的是，一旦结婚，原遗嘱自动失效。 It is worth remembering that previous wills are nullified automatically upon marriage.

[例句] 现在签订的合同可能在将来的某一天就会失效。 A contract signed now might be invalidated at some future date.

productiveness，efficiency，productivity，workpiece ratio ；

[例句] 总之，易货贸易是一种效率很低的交易形式。 Overall, barter is a very inefficient means of organizing transactions.

[例句] 非国有企业逐渐挤掉了效率低下的国有企业。 Non-state firms gradually elbow aside the inefficient state-owned ones.

of no avail，to no avail，invalid，null and void，be of no effect ；

[例句] 如果可的松无效，我恐怕只能动手术了。 If the cortisone doesn't take, I may have to have surgery.

[例句] 令人震惊的是，这种既无效又危险的手术直到20世纪30年代才被废止。 Shockingly, this useless and dangerous surgery did not end until the 1930s.

effective，valid，efficacious，availability，be good for ；

[例句] 如果使用得当，避孕套是很有效的避孕手段。 Condoms are an effective method of birth control if used with care.

[例句] 服用避孕药是最有效的避孕方法。 The pill is the most efficient method of birth control.

effect，result，[剧] sound effects；

[例句] 若IBM公司和苹果公司联手将会有什么效果呢？ What will be the effect of the alliance between IBM and Apple?

[例句] 调整天线的位置和方向以达到最佳接收效果。 Adjust the aerial's position and direction for the best reception.

effectiveness，efficacy，efficiency，utility，avail ；

[例句] 草药的医疗效用 the therapeutic properties of herbs

[例句] 这些植物具有药物效用. These plants have medicinal properties.

aftereffect，future performance ；

[例句] 测后效可掌握储层情况. The reservoir situation can be mastered after testing trip gas.

[例句] 轨道轰炸技能的后效对于高级甲建筑物不再有100%透效果. Orbital Bombardment ability's later effects no longer have 100 % penetration against Building High.

effect，result ；

[例句] 我相信埃莉诺所做的工作会在妇女中有所成效。 Eleanor's work among the women will, I trust, bear fruit.

[例句] 我期盼着能与他建立长期而有成效的合作关系。 I am looking forward to a long and successful partnership with him.

come into force [operation]，go into effect，become effective，take effect，in operation ；

[例句] 他有权维持法庭判决，批准死刑生效。 He can let the court's decision stand and permit the execution.

[例句] 马尔科姆的合同将与他手头的合同同时生效。 Malcolm's contract will run in tandem with his existing one.

render a service to，serve，potence，effect，effectiveness ；

[例句] 我认为他为英格兰队效力时不可能充分发挥自己的水平。 I don't think he could do himself justice playing for England.

[例句] 对于他们长期以来忠诚的效力我非常感谢。 I thanked them for their long and loyal service.

imitate，follow the example of，be imitative of，in the wake of ；

[例句] 他仿效恶例. He copied after bad precedents.

[例句] 她仿效哥哥的举止. She models her behavior upon her brother's.

potency，efficacy，usefulness，effect，efficiency ；

[例句] 看不见的手的效能必然要相应地降低. The virtues of the invisible hand must be that much discounted.

[例句] 然而, 它不需要被吸收的水汽层来发挥效能. However, it does not require an absorbed vapour layer to become effective.

effect，efficiency，behaviour，efficacy，virtue ；

follow the example of，model oneself on，learn from，emulate，imitate ；

[例句] 随后150年，许多人效法于他。 Over the next 150 years, many others followed his lead.

[例句] 供学生效法的榜样 a paradigm for students to copy

yield results，produce effects，bear fruit，effects ；

[例句] 总统的话在提高全国人民的信心方面收效甚大. The president's statement went a long way towards reassuring the nation.

[例句] 再说, 我们怎么知道CP21对每个人都能收效? Now, how do we know that CP 21 will work for everyone?

synergism，synergia，synergy ；

[例句] 这可以从增效剂上加以改进. This can be improved by the addition of an adjuvant.

[例句] SMA与上述表面活性剂的复配增效作用比SSMA要弱. The synergism of SMA with above surfactants is weaker than SSMA.

work in the service of，work for，service，offer one's services ；

[例句] 她夸张地鞠了个躬。“阿纳斯塔西娅·克鲁布尼克，随时为您效劳，”她说。 She bowed dramatically. "Anastasia Krupnik, at your service," she said.

[例句] 如果我可以效劳的话，敬请吩咐。 If I can be of service, I am at your disposal.

beneficial result，effectiveness，benefit，achievements ；

[例句] 银行的经营必须追求成本效益。 The bank must be run in a cost-effective way.

[例句] 采用的方法很老套，没什么效益。 The methods employed are old-fashioned and uneconomical.

pledge loyalty to，devote oneself heart and soul to，fealty，allegiance，homage ；

[例句] 宪法规定，议员必须宣誓效忠。 The constitution requires members of parliament to take an oath of allegiance.

[例句] 法国国王不对任何人效忠。 The kings of France paid homage to no one.

be successful，bear fruit，do execution，prove effective ；

[例句] 那种方法不奏效的时候，他们有时会想到要寻求帮助。 When that doesn't work they sometimes have the sense to seek help.

[例句] 这些方法中有一些会奏效，其他的则行不通。 Some of these methods will work. Others will not.