1. I am late for school from time to time.

I will come to school earlier.
I will come to school on time.

2. I don't exercise regularly.
I will take exercise regularly.
I will exercise at times.

3. I don't help Mother clean the house.
I will help her clean the house.
I will try to help my mother clean the house.

4. I don't study hard.
I will study hard.
I will pay attention to study.

5. I go to a PC room too often.
I will not go to a PC room too often.
I won't go to PC room any more.

6. I go to a singing room sometimes.
I won't to go to a singing room at all.
I will never go to a singing room.

7. I make noises in the classroom.
I won't make noises in the classroom.
I will be quiet in the classroom.

(Would you check the sentences? Are they all grammatical? If any errors, correct them, please.)

1 is fine.

2 -- I'd remove the word "take" in the second sentence.

3 & 4 are fine.

5 -- Add "a" or "the" before "PC" in the third sentence.

6 -- Do you mean that the room sings? Or that it's a room where singing occurs?

7 -- I'd change "noises" to "noise" in the first two sentences.

The sentences are grammatically correct, but there are some changes that can be made to improve the clarity and flow of the sentences. Here are the revised versions:

1. I am occasionally late for school.
- I will make an effort to arrive at school earlier.
- I will strive to come to school on time.

2. I do not exercise regularly.
- I will make it a habit to exercise regularly.
- I will commit to exercising consistently.

3. I do not help Mother clean the house.
- I will assist her in cleaning the house.
- I will make an effort to help my mother clean the house.

4. I do not study hard.
- I will dedicate more time and effort to studying.
- I will be more focused and diligent in my studies.

5. I go to a PC room too often.
- I will reduce the frequency of my visits to the PC room.
- I will refrain from going to the PC room excessively.

6. I go to a singing room sometimes.
- I will avoid going to the singing room altogether.
- I will never go to a singing room again.

7. I make noises in the classroom.
- I will refrain from making noises in the classroom.
- I will maintain a quiet demeanor in the classroom.

Note: The revised sentences provide clearer expressions of the intentions to improve and change certain behaviors.