[填空题]
A police department has 4 mym(-kgme ,5:8irxr 1 ysute* oale and 7 female officers. A special groupb1ac v -0;smbp of 5 officers is to be assembled for an undercovera0 s;v-cb1mp b operation.
1. Determine how many possible groups can be chosen.
2. Determine how many groups can be formed consisting of 2 males and 3 females.
3. Determine how many groups can be formed consisting of at least one male.
