Now let me tell you about the work I have been doing with the UN. My job with the UN is not paid but voluntary, and  小题1:  I said before, I visit countries where the UN has programmes to help people. So,  小题2:do I help by visiting these countries? Well,  小题3: I visit these countries, the television and press will follow and record my visits. This will increase people’s knowledge of the work of the UN. In addition, my visits will encourage people   小题4:  are working on the projects and draw local people’s attention 小题5:  the situation.

I have visited many countries in Africa. Recently, I was fortunate 小题6: to travel to South Africa, where I met some women who have organized themselves into a group. They collect approximately 1.35 yuan per day from each member and add  小题7: to some money contributed by the government. With this, the women have enough money to acquire materials to make baskets. They then sell these at the market for  小题8: profit. With luck their group will be able to expand and maybe set up a shop. Such programmes can transform people’s lives by giving them the ability to provide for themselevs and their families.

肺静脉的脉冲多普勒频谱中的负向波（AR波）出现于（）。

A.心房的快速射血期

B.心房的收缩期

C.心房的等容舒张期

D.心房的舒张期

E.心室的快速舒张期