Test analysis: the situation of a shift is: (Monday, Tuesday), (Monday, Wednesday), (Monday, Thursday),
(Tuesday, Wednesday), (Tuesday, Thursday), (Wednesday, Thursday), * * Among them, (Monday and Wednesday),
(Tuesday, Thursday) shows that the same person is not on duty continuously, so the required probability is.
Comments: To find the probability of classical probability, we can only determine the number and total number of required events, and then find out their proportions.