简介:摘要人类的生命起源于受精卵,受精卵是卵细胞和精子结合形成的,而卵细胞和精子又各自是如何发育成年又“相遇相知到相爱”的呢?神秘的面纱需要我们层层揭开,感受生命的奇妙。
简介:StephenHawking,thefamous1)astrophysicist,saysweneedtospreadintoouterspace.Ifwedon't,hesays,itwillbedifficultfortheworldto“2)avoiddisasterinthenexthundredyears,letalonethenextthousandormillion.”HawkinghasLouGehrig'sdisease.Hehastospeakwiththeaidofa3)computersynthesizedvoice.