D. forbid the use of social networks during work time

30. The main purpose of this passage is to _________.

A. share experiences in using social media

B. provide some advice on social problems

C. raise public awareness of social problems

D. remind people to wisely use social media

31. Which of the following shows the development of ideas in this passage？

I：Introduction P：Point Sp：Sub-point（次要点） C：Conclusion

D

China became the first country to clone a monkey using non-reproductive（非生殖的）cells, reducing the need to raise lab monkeys and paving the way for more accurate, effective and affordable animal tests for new drugs, scientists said on Thursday .

By December, the Institute of N euroscience of the Chinese Academy of Sciences had created two clone macaques（猕猴）named “Zhong Zhong” and “Hua Hua” by nuclear transferring of somatic cells（体细胞） - any cell in the organism other than reproductive cells.

Tetra, a monkey born in 1999, is the world’s first cloned monkey, but it was done by using a simpler method called embryo splitting（胚胎分割）, and cannot be genetically changed to suit the experimental need. Cloning a monkey using somatic cells has been a world-class challenge because a monkey that shares its genetic makeup, and therefore all of