题目

AIDS researchers say they still have much work to do on a vaccine (疫苗) against HIV. But the first reports of some success have raised hopes.    1   The study was designed to test for two abilities. One was the ability of the vaccine to prevent HIV infections. The other was its ability to reduce the amount of virus in the blood of people who became infected during the study. Volunteers received vaccinations over a period of six months and were tested for HIV for an additional three years. The study began in 2003. It was the largest AIDS vaccine trial yet.  2    Half recei在实验中，要称取一定质量的固体药品应选用（　　）A．漏斗B．量筒C．胶头滴管D．托盘天平