Laugh and say: I'm not lying.

Naughty said: Xiaoxiao is lying.

Qing Qing said: Naughty and smiling are deceptive.

Clever children, do you know which one of them must be lying?

This year, our Yucai Group has four new young teachers, and our Yucai Group has four primary schools. We will arrange 1 teacher for each primary school. Three related teachers suggested this arrangement:

Miss Li: C goes to educate a primary school and B goes to educate a middle school.

Miss Wang: C goes to the second primary school and D to the third primary school.

Teacher Zhang: A goes to the second primary school and D to the fourth primary school.

The principal of the general school finally absorbed half of the suggestions of the relevant teachers. Do you know how the headmaster divided them?

There are 32 football teams participating in the World Cup. They were divided into eight groups, and the first group match was held. Every two teams in the group will play a game. Do you know how many World Cup group matches have been played?