CCTV interview: Nuclear Security Summit achievement

Now, let's resume our discussion with Mr. Hua.

Question 2: The summit has adopted a communique that includes a US proposal to "secure all vulnerable nuclear material in four years."

Can you elaborate on the achievement? And as different countries are taking different positions, could you explain the main differences?

Chinese President Hu Jintao(4th R,front)poses for a group photo with other world  leaders during the Nuclear Security Summit at the Washington Convention Center in  Washington,April 13,2010 0.(Xinhua/Li Xueren)