In the table tennis singles competition between students A, B and C, two students should be selected to play the first game. Please use tree diagram or list method to find out.

Test analysis: th

Test analysis: this question needs two steps to complete, so it is relatively simple to get the total number of all cases and the number of qualified cases by tree diagram or list method; The ratio of the two is the probability of its occurrence.

Solution: Draw a tree diagram as follows:

6 points

There are six possible situations, two of which are the combination of students A and B..

therefore

Comments: This question examines the solution of probability and classical probability by list method or tree drawing method. List method or tree diagram method can list all possible results without repetition or omission, which is suitable for two-step events. The knowledge points used are: probability = the ratio of the number of cases required to the total number of cases.