valuable for research on new plant species and for medical research on animals. However, the process of cloning is difficult to undertake.

Many attempts to clone mammals failed. The breakthrough that scientists made in history is in the year 1996. The first success cloning, Dolly the sheep, made the whole scientific world follows its process, though it had more problems than the normal sheep. On the other hand, Dolly's appearances raised a storm of objections and had a great impact on the media and public imagine. Different people have different opinions on it. However, scientists still wonder if cloning will help or harm you and where it is leading us. Maybe in the 21st century, cloning will be the biggest moral dilemma.

答案:

1. 【解析】将第一句中的第二个here去掉。此处地点副词here重复。

2. 【解析】将第二句中的make改为making。此句中of为介词, 后用动词的-ing形式作宾语。

3. 【解析】将第三句中的use改为uses。由前面的修饰词two可知, 此处需用名词的复数形式。

4. 【解析】在第五句中的第一个is之后加that。此处为表语从句, 缺少引导词。

5. 【解析】将第九句中的success改为successful。此处需用形容词形式修饰后面的名词cloning。

6. 【解析】将第九句中的follows改为follow。此处为"make +宾语+宾语补足语", 需用动词原形作宾语补足语。

7. 【解析】将第十句中的appearances改为appearance。Dolly的出现应该用单数形式。

8. 【解析】将第十句中的imagine改为imagination。public在此作形容词后需用名词形式。

9. 【解析】将第十二句中的if改为whether。whether与or连用。

10. 【解析】将第十二句中的you改为us。根据and并列句中的表达可知, 此处应该为us。