(1) has 3! =6 kinds. On the first day, you can arrange any 1 for three people, and there are three possibilities; You can arrange 1 for the remaining two people the next day, and there are two possibilities; The last day can be ranked last 1, so it is 3×2× 1=6.

(2) Three kinds, just list them directly. a，B，C，B，C，B。

(3)3/6= 1/2