Reference answer: 1. First, it means that the person who called the door came straight in. Second, it means that the boy sneaked into the classroom without even typing the report.

(1) "mumble" refers to a scene where a little boy wants to say "but what if the puppy comes by himself" in front of the teacher but hesitates to say it.

(2) Expression description. I wrote the thoughts and feelings that the little boy was shocked, puzzled and distressed by the old headmaster's behavior of kicking the puppy. It also laid the groundwork for the little boy's accidental departure from school.

3. The function of ellipsis is to indicate language interruption. The function of exclamation point is to express the pause at the end of a sentence with strong feelings. Both punctuation marks show "I"' s anger at the little boy for disturbing the classroom order after he brought the puppy into the classroom.

We should be kind to left-behind children, care about their life and study, and care about their emotional world. We should also be kind to animals, because animals are our partners.