Dongdong wants to take part in calligraphy and can't clean it up. How can he ask for leave?

Dongdong wants to take part in calligraphy, so he can't ask for cleaning such a holiday: hello, teacher! I can't take part in the cleaning because my calligraphy time conflicts with the cleaning time. Ask the teacher for understanding and hope the teacher will approve! Interviewee: Dongdong. This kind of leave not only reflects Dongdong's respect for the teacher, but also explains the events and reasons of the leave, and finally obtains the teacher's understanding. Dongdong not only simply outlines that he should participate in calligraphy instead of cleaning, but also expresses it clearly and clearly.