I have a important exam afterin a month's time, so I'm practiceing English in theat school. I have a important exam in a month's time, so I'm practicing English at school.

Instead of "in a month's time" you could also use "a month from now"

I have an important exam afterin a month, so I practice English in theat school. I have an important exam in a month, so I practice English at school.

I understand what you're saying, the corrections just make it sound more like it's coming from a native speaker.

I have an important exam afterin a month, so I practice English in theat school. I have an important exam in a month, so I practice English at school.

Use 'an' before words that start with a vowel. --> a cat, a dog, a book BUT an idea, an event, an important exam When you want to say something will happen after a period of time, say 'in'. --> I have a test in two days. We have a meeting in an hour. We'll get married in a year. Use 'at' when describing the location where you do something. --> I cook at home. I study at school. I read at the library.

I have a important exam afterin a month, so I practice English in the school. I have a important exam in a month, so I practice English in the school.

But the studying for the exam is boreding. But studying for the exam is boring.

"bored" describes a state of being, while "boring" describes what makes you bored.

But the studying for the exam is boreding. But studying for the exam is boring.

But the studying for the exam is boreding. But studying for the exam is boring.

"Studying' instead of 'the study' because you're describing the process of studying as boring. 'A study' actually means a research paper. Say 'the exam' because you are referring to a specific exam in the future and not just in general. Not putting any article or possessive pronoun before your noun is grammatically incorrect. --> I'm studying for the exam OR I'm studying for my exam (there's a specific exam I'm studying for) 'Boring' is an adjective to describe something. 'Bored' is to describe how you're feeling. --> I'm bored with studying (you feel bored) OR Studying is boring.6

But the, studying for the exam is boreding. But, studying for the exam is boring.

Most of the sentences I read are about someone's peaceful daily life. Most of the sentences I read are about someone's peaceful daily life.

(I didn't change "peaceful", but it seems like you probably meant something like "monotonous" instead)

Most of the sentences I read are about someone's peaceful daily life. Most of the sentences I read are about someone's peaceful daily life.

Remember to put articles before your nouns.

Most of sentences I reoad are about someone's peaceful daily life. Most of sentences I road are about someone's peaceful daily life.

I'm indifferent to them. I'm indifferent to them.

"I'm indifferent" can sound somewhat neutral - based on what you wrote in Japanese you could strengthen this to emphasise how much you do not care about them. "I have no interest in them." gives a stronger impression of not caring.

ThusSo, I want to learn English with sentences read in the real world. So, I want to learn English with sentences in the real world.

"Thus" works, and personally I love "thus", but you don't hear it very often in everyday English anymore. It might be used in a really formal setting (like a courtroom), or perhaps a movie.

Thus, I want to learn English with sentences read inwritten about the real world. Thus, I want to learn English with sentences written about the real world.