当谈及克隆恐龙时仍旧有麻烦。某些植物像胡萝卜已经被克隆了，但是克隆动物的尝试却不那么成功。
In the movie Jurassic Park，scientists clone dinosaurs by using the DNA that was preserved for millions of years.However，there is trouble when the cloned dinosaurs turn out fiercer and smarter than expected.Can dinosaurs really be cloned? Theoretically，they can；all that would be required is DNA from an extinct dinosaur and a currently living closely related species which could act as a surrogate mother.
Actually，cloning is a phenomenon that occurs naturally in a wide variety of species.Whenever you see a pair of identical twins，they are examples of nature's clones.Although scientists have been cloning certain plants like the carrot quite successfully for decades，attempts at cloning animals have not been as successful.However，they began long before the birth of Dolly，the sheep—the first mammal successfully cloned.
Cloning humans does give rise to some misgivings，raising a number of moral problems involved.In fact，the social influences of producing humans artificially were brilliantly explored in the famous novel Brave New World by Aldous Huxley，and also in the movie The Island.
Human cloning is basically about creating a genetically identical copy of a previously existing person.Why would some people choose to clone human beings？Well，generally，it could make couples unable to have babies have their own children.Replacing a dead child is also another reason why some people have expressed interest in the technology.
[阅读障碍词]
1．surrogate adj. 替代的；代理的
2．misgiving n. 疑虑；担忧
3．genetically adv. 基因地；遗传学地
