一、单词填空
1、with the loud noise outside，i can hardly c _______ on my study.
2、after he decided to follow in lei feng’s footsteps, he pushed ahead with his d_______.
3、the first mammal to be cloned s________ from an adult cell was dolly the sheep.
4、while cloning human embryos is not l_______ in many countries, some scientists are already pushing ahead with research in order to produce
