Lily的Scalers Talk第八轮新概念朗读持续力训练Da

Lesson 20-1      Snake poison

How it came about that snakes manufactured poison is a mystery. Over the periods their saliva, a mild, digestive juice like our own, was converted into a poison that defies analysis even today. It was not forced upon them by the survival competition; they could have caught and lived on prey without using poison, just as the thousands of non-poisonous snakes still do. Poison to a snake is merely a luxury; it enables it to get its food with very little effort, no more effort than one bite. And why only snakes? Cats, for instance, would be greatly helped; no running fights with large, fierce rats or tussles with grown rabbits -- just a bite and no more effort needed.

poison /ˈpɔɪzn/  毒药，毒物，毒素;

saliva /səˈlaɪvə/ 唾液

digestive /daɪˈdʒestɪv/   助消化的;和消化有关的

mild /maɪld/  温和的;轻微的;和善的;

convert  /kənˈvɜːrt/  转换;转化;(使)转变;

defy /dɪˈfaɪ/  不可能，无法(相信、解释、),   违抗;藐视;反抗

over the periods  经过很长时间

force upon  把……强加于……

prey /preɪ/  猎物;受害者;受骗者

fierce  /fɪrs/ 凶猛的

tussle /ˈtʌsl/  扭打，争斗