2. Put Girl A aside and four boys line up, so that * * * has five vacancies for girls to insert, and one * * has m-girls, and the probability of choosing a vacancy is one in five (ignoring other factors, because the topic only asks Girl A and Boys, the probability of girls ranking in each vacancy is one in five). After that, it is easy to get the distribution list according to the position of the vacancy. . . Mathematics expectation is two. . . Students, use your head more AA, you'd better draw a sketch.