[urgent! ! ! I want to ask, if you send an email to the teacher asking not to fail, how should you write the title of the email?

I haven't heard of this. Some people go directly to the teacher, but pay attention to make sure that you really failed this course, and that you didn't fail too much, and your performance in class was not bad. The teacher knows about you. . .

You can write it like this

Pay tribute to Teacher XX who loves you.

I'm XX from Class XX of XX College, and this year's final exam is due to XX reasons (I didn't review well, so I'd better get sick or something; Sudden emergency in the examination room; Wait, it must be a sincere force majeure reason acceptable to the teacher. ) I feel that I didn't do well in the exam, and I am worried that I won't get it. I am very entangled in my heart and sent you this letter. . .

Please imagine for yourself that there is really no such talent.

Just write' a letter from XX to Teacher XX' as the title and theme, without naming the theme. This is not a glorious thing.