secondness第二性secondadj.第二的；次等的；再一个的num.第二n.片刻；秒adv.第二；其次v.支持；赞成；附和；调派Second stage attitude control engine二级姿控发动机second generation cordless telephone第二代无绳电话Second Assistant Bartender Zhang Yan第二副调酒师张岩second generation wavelets transform第二代小波second-stage hydrogenation reactor二段加氢反应器second order boundary value problems两点边值问题second language and foreign language第二语言和外语second-order sufficiency condition二阶充分条件second liner timbering opportunity.二衬支护时机：second eritieal fluidization velocity第二临界流化速度

1. By replacing your air filter annually, or biannually if you live in a dusty area, you'll ensure the engine can breathe freely.
   每年换一次过滤器或者在沙尘多的地方每半年更换一次能保证你的爱车引擎自由呼吸。