They find it difficult to pump themselves up for the games.他们感到要为自己加油打气，自信满满地去打比赛并不容易。Age diminishes the heart's ability to pump harder and faster under exertion.随着年龄的增加，人在消耗体力时心脏的输血能力和输血速度会有所减弱。He ran in every five...
Motherhood has both its pros and cons.当妈妈既有好的一面，也有不好的一面。The pros and cons cancel out.正反两种意见抵消.They sat for hours debating the pros and cons of setting up their own firm.他们在一起坐了数小时，讨论自己创办公司的利弊。...
锑的百分含量由各蓄电池生产厂自己掌握.The percentage of antimony may be left to the battery manufacturer.含锑的铅较化工铅好些,由于它有更好的抗蚀性及强度.Antimonial lead is preferable to chemical lead because of its greater corrosion resistance and strength.一种蓝灰色...