Can you please tell me if the parts included in brackets are grammatically wrong? Thank you.

1) Slaves had to harvest and grow sugar cane (not sugar canes).
2) Slaves couldn’t speak their language, call themselves with their names or practice their religion because slave owners were frightened of (?) slaves’ customs.
3) In spite of that (this?), slaves sang haunting songs.
4) They were denied the knowledge to read and write (can you say that?).
If they misbehaved, they were subjected to corporal punishment(s).
5)The Civil War between the Northern and the Southern States ended in 1865 with the abolition of slavery.
6) Winston is a frail, thin, fair-haired, thirty-nine-year-old man.
7) He lives a squalid existence in London, the chief city of Airstrip one, that is (lies?) in the totalitarian super-state of Oceania,
8) Through the window pane of his apartment he can see a poster on the opposite house-portraying a black-mustached man, the image of the party in its public representations.

1) Slaves had to harvest and grow sugar cane.

2) Slaves were not allowed to speak their own languages, call themselves by their own names, or practice their own religions because slave owners were frightened of slaves’ customs.

3) In spite of this, slaves sang haunting songs.

4) They were forbidden from learning to read and write. If they misbehaved, they were subjected to harsh corporal punishment.

5)The Civil War between the northern and the southern states ended in 1865 with the abolition of slavery.

6) Winston is a frail, thin, fair-haired, thirty-nine-year-old man.

7) He lives a squalid existence in London, the chief city of Airstrip One, that lies in the totalitarian super-state of Oceania.

8) Through the window in his apartment, he can see a poster on the opposite house, portraying a black-mustached man, the image of the party in its public representation.

1) The use of "sugar cane" is correct. No plural form is needed in this sentence.

2) The only grammatical issue in this sentence is the missing word after "frightened of." You could complete the sentence by saying "frightened of the slaves' customs."
3) Both "that" and "this" can be used in this sentence, depending on the context. If you are referring to something specific that was mentioned before, you would use "that." If you are introducing something new or referring to something more immediate, you would use "this."
4) The phrase "They were denied the knowledge to read and write" is grammatically correct.
5) The sentence is grammatically correct. No changes are needed.
6) The sentence is grammatically correct. Multiple adjectives can be used to describe a noun.
7) The correct word here is "lies." It refers to the location of Airstrip One.
8) The sentence is grammatically correct. No changes are needed.