CLONING：WHERE IS IT LEADING US?

　　Cloning has always been with us and is here to stay. It is a way of making an exact① copy of② another animal or plant. It happens in plants when gardeners take cuttings③ from growing plants to make new ones. It also happens in animals when twins④ identical⑤ in sex and appearance are produced from the same original egg. The fact is that these are both examples of natural clones⑥. 　　①exact/Iɡ'zækt/adj.精确的；准确的

　　②make a copy of (＝copy)复制

　　of making ...作way的定语。

　　③cutting/'kʌtIŋ/n.剪枝；剪报；剪纸

　　④twin/twIn/n.双胞胎之一；孪生儿之一 adj.成对的；成双的

⑤identical/aI'dentIkl/adj.同一的；一模一样的

　　⑥The fact is that ...中，that引导表语从句。 　　克隆：它将把我们引向何方？

　　[第1段译文]

　　克隆一直与我们同在，而且它还要持续下去。这是一种用来生产与原型完全相同的动植物的方法。当园艺师从生长着的植物上剪下枝条来培植新植物时，就会产生这种现象。这种现象也发生在动物身上，从同一个原生卵子产生性别和相貌相同的双胞胎也是克隆。实际上，这些都是自然克隆现象的例子。　　

　　Cloning has two major uses. Firstly, gardeners use it all the time⑦ to produce commercial⑧ quantities of⑨ plants. Secondly, it is valuable for research on new plant species and for medical research on animals. Cloning plants is straightforward⑩ while⑪ cloning animals is very complicated⑫. It is a difficult task to undertake⑬. Many attempts to clone mammals⑭ failed. But at last⑮ the determination and patience of the scientists paid off⑯ in 1996 with a breakthrough⑰ - the cloning of Dolly the sheep. The procedure⑱ works like this：

　　1　Female sheep A provides an egg cell.

　　2　The nucleus⑲ is removed from⑳ the egg cell.

　　3　The egg cell is ready for a new nucleus.

　　4　Female sheep B provides a somatic\s\up1(21(21) cell for the clone. The nucleus of this cell contains all the genes needed to produce a new sheep\s\up1(22(22).

　　5　The nucleus is taken out of the somatic cell.

　　6　The nucleus from sheep B and the egg cell from sheep A are joined using electricity\s\up1(23(23).

　　7　The cell divides and grows into an embryo\s\up1(24(24).

　　8　The embryo is put into female sheep C, who becomes the carrier\s\up1(25(25) of the clone\s\up1(26(26).

　　9　The lamb is the clone of the donated\s\up1(27(27) cell from Sheep B which provided the nucleus\s\up1(28(28). 　　⑦all the time 一直

　　⑧commercial/kə'mɜːʃl/adj.商业的；贸易的

　　⑨quantities of"大量的"；修饰可数名词复数或不可数名词

　　⑩straightforward/ˌstreIt'fɔːwəd/adj.简单的；直接的；坦率的

　　⑪while在此表示"而；却"，是并列连词，表对比关系。

　　⑫complicated/'kɒmplIkeItId/adj.复杂的；难懂的

　　⑬undertake/ˌʌndə'teIk/vt.(undertook; undertaken)着手；从事；承担

　　不定式短语to undertake作定语，修饰task。

　　⑭不定式短语to clone mammals作定语，修饰attempts。

　　⑮Firstly ... Secondly ... But at last ... "首先......其次......最后......"，表示论述顺序。

　　⑯pay off 得到好结果；取得成功；偿清

　　⑰breakthrough/'breIkθruː/n.突破

　　⑱procedure/prə'siːdʒə/n.程序；步骤；手续

　　⑲nucleus/'njuːklIəs/n.原子核；中心

　　⑳remove ... from ... 将......从......移走

　　\s\up1(21(21)somatic/səʊ'mætIk/adj.躯体的；肉体的；细胞体的

　　\s\up1(22(22)过去分词短语needed to ...作定语，修饰genes。

　　\s\up1(23(23)现在分词短语using electricity作方式状语。

　　\s\up1(24(24)embryo/'embrIəʊ/n.胚；胚胎；萌芽时期

　　\s\up1(25(25)carrier/'kærIə/n.携带者；搬运工；运输工具

　　\s\up1(26(26)who引导非限制性定语从句，修饰先行词female sheep C。

　　\s\up1(27(27)donate vt.捐赠；捐献

　　\s\up1(28(28)which引导定语从句，修饰Sheep B。