恐龙的回归？

[第1段译文]

克隆凶猛和灭绝的野生动物的可能性一直使电影制片商感到兴奋。然而他们并不是唯一对此感到兴奋的人！在《侏罗纪公园》这部影片中，有一位科学家克隆了好几种不同的绝种恐龙。类似这样的电影很受欢迎，证明了这一想法使人们感到既兴奋又恐惧。但事实上，要想克隆绝种动物，我们还有很长的路要走。科学家们现在还在进行克隆哺乳动物实验。这是因为克隆哺乳动物仍然还是一门新的科学，它是从20世纪50年代才开始认真进行研究的，如下列所示：

20世纪50年代：克隆青蛙

20世纪70年代：用老鼠胚胎进行研究

1979年：对羊和老鼠的胚胎进行研究

1981年：首次对老鼠进行实验性的克隆

1983年：首次对奶牛进行实验性的克隆

1996年：首次克隆哺乳动物(多莉羊)

2000年：奶牛生野牛

2001年：中国首次克隆出双胞胎小牛

2002年：首次克隆猫

2005年：首次克隆狗

...... 　　　

　　From time to time⑯ people suggest that extinct animals like dinosaurs, can possibly be brought back to life⑰ through cloning. Unfortunately, with what we know now, this is either impossible or⑱ unsuitable. There are many reasons.

　　•The initial⑲ requirement is that you need perfect DNA⑳ (which gives information for how cells are to grow)\s\up1(21(21).

　　•All efforts of cloning an animal will be in vain\s\up1(22(22) if there is not enough diversity\s\up1(23(23) in the group to overcome\s\up1(24(24) illnesses. Diversity in a group means having\s\up1(25(25) animals with their genes arranged in different ways\s\up1(26(26). The advantage is that if\s\up1(27(27) there is a new illness some of these animals may die, but others will survive and pass on the ability to resist\s\up1(28(28) that disease to\s\up1(29(29) the next generation. The great drawback\s\up1(30(30) to cloning a group of animals is that they would all have the same arrangement of genes and so might die of\s\up1(31(31) the same illness. Then none of them would be left to continue the species.

　　•It would be unfair to clone any extinct animals if they were to live in a zoo\s\up1(32(32). A suitable habitat would be needed for them to lead a natural life\s\up1(33(33). 　　⑯from time to time (相当于sometimes, not very often)不时；偶尔

　　⑰bring back to life 使复生；使复活

　　⑱either ... or ... 或者......或者......；要么......要么......(连接并列结构)

　　⑲initial/I'nIʃl/adj.最初的；开始的

　　⑳DNA 脱氧核糖核酸

　　\s\up1(21(21)that引导表语从句， which引导定语从句，修饰DNA。

　　\s\up1(22(22)in vain 白费力气；枉费心机

　　vain/vein/adj.虚荣的；自负的；徒劳的

　　\s\up1(23(23)diversity n．差异(性)；不同(点)；多样化

　　\s\up1(24(24)overcome v．战胜；克服　\s\up1(25(25)mean doing sth. 意味着做某事

　　\s\up1(26(26)with their ...是with的复合结构， genes与arrange之间为被动关系。

　　\s\up1(27(27)The advantage is that if ..., that引导表语从句，在表语从句中包含if引导的条件状语从句。

　　\s\up1(28(28)resist/rI'zIst/vt.抵抗；对抗

　　\s\up1(29(29)pass on ... to ... 把......传给......；把......转交给......

　　\s\up1(30(30)drawback/'drɔːbæk/n.缺点；不利条件(常与of/to搭配)

　　\s\up1(31(31)die of 死于(疾病、衰老等自身原因)

　　\s\up1(32(32)It would be ... if they were to live ...用了与将来事实相反的虚拟语气。

　　\s\up1(33(33)lead a natural life 过正常的野生生活