I've practiced again today and i would like to know if my sentences are correct. (I hope I'm not bothering you already)
-I see you. (Is it really the verb "to watch", because in this case google translates it as "to look for")
내가 너를 봐요.
-He cleans the table in the kitchen. (Here I wanted to know if the particles are correct or not)
그가 식탁을 부엌에서 청소해요.
-You read a book. (I don't know why, but google translates 책자 to "books" (plural))
네가 책자 읽어요.
By the way, is putting 을 at the end of a word the only thing you have to do to say it's plural?
-Does he go in the kitchen? (Here again, are the particles correct? 에 is used to precise there is a movement right?)
그가 부엌에 가요?
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내가 너를 봐요.
나는 당신를 봐요 - 나는 is better for your intended meaning because you are saying "I am seeing you." Also, if we are going to use the polite ending "요" then we would use a polite form of the word 'you'(당신) or a person's name or title. Be careful with the use of 보다 because it can also mean 'watch over/taking care of/making an exception for,' and not just 'to see' (it can even mean 'to try' in some cases)
Some other suggestions:
나는 너를 본다 - 나는 너을 보인다 - 나는 너을 보고 있다 - 나는 선생님을 보고 있어요
보인다 - 본다 - see (you)
보고 있다 - seeing (you)
보았다 - 봤다 - saw (you)
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그가 식탁을 부엌에서 청소해요 (The particles here look fine to me but the word order makes it look as if he brought the table into the kitchen to clean it. Also Koreans generally use '닦다' when referring to cleaning a table)
그가
부억에 있는 식탁을 닦아요 -He cleans the table
that is in the kitchen.
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네가 책자 읽어요. (we are not going to mix informal and polite when addressing or commenting to that person 네가 does not go with 요 - please choose one style or the other)
네가 책을 읽다 / 당신이 책을 읽어요 --now let's see an expression we can actually use '네가 책을 읽구나!' You read books! (wow) 당신이 책을 읽군요!
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By the way, is putting 을 at the end of a word the only thing you have to do to say it's plural?
을/를 doesn't make anything plural -- 을/를 objectifies 나
를 = me, "me" can receive action e.g. She loves ME -- 그녀는 나
를 사랑해요. To make many nouns plural in Korean the particle 들 can be used 책들 - books, 사람들 - people, 문제들 - problems; however, some items are already plural, such as the word 'parents' (부모), so when we say 'your parents' we don't use 들 because that would mean 'many sets of parents.'
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그가 부엌에 가요? --Perfect! Good job!
We could equally say 그가 부엌으로 가요? Is he going into (toward) the kitchen.
depending on context 에 can mean 'at' a place, 'in' a place, 'to' a place, and it can also indicate a period of time.
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Disclaimer:
I am no expert in Korean grammar. There may be errors in my explanations but I have given you the best information possible according to my Knowledge. You may want to Google search to see if there are any sites that specialize in giving corrections by native speakers.