1.how often does Minh brush his teeth?
2.why does Simon have a lot of pain now?
3.How did you feel after eating that food?
4.when did Nga go to the dentist?
5.Who will check your teeth?
6.How long did it take for Dr.phong to fill Van's tooth?
7.where are your brother going to?
8.What did Mr.Cuong do at 5.30 yesterday?
9.Whose letter did Hoa receive 5 days ago?
10.How many students are there in Lien's class having toothache?