有答案 求大虾解释一下。。。不懂
A committee to monitor the effects of new policies on AIDS is to be formed from 3 Psychologists (Patricia, Peter, Pauline), 3 Physicians (Michael, Mary, Maureen), 2 Social Workers (Steve, Susan), and 3 Economists (Edward, Eileen, Edith). The committee must include exactly 2...