自动失效的英文

the old contract will lose its value at the same time

expirehttp://www.medscape.com/viewarticle/460159(上面那个是讨论药品失效的，化学药剂应该用相同的词吧)

the former/previous contract will be invalidated at the same time

lose effectiveness

失效 lose efficacylose effectivenesscease to be effectivebe no longer in forcebecome invalid

“汽车上的eco就是汽车经济驾驶模式。 eco是一个英文简称,它由Ecology(环保)、Conservation(节能)和Optimization(动力)合成而来。Eco模式还分为主动式eco驾驶模式和非主动式eco驾驶模式,当仪表盘eco指示灯亮起时,表明车子经济模式已经开启。