First: The differences between that, if, which, who and whom. "That" is used for reported speech. An example would be: "He said that [clause]." "If" is used for reported speech, specifically for enquiring about something. An example would be: "He asked if [clause]." "Which" is used (usually formally) for objects. An example would be: "The car which was parked here." If the clause doesn't change the meaning of the sentence, then a comma will be added before "which" and after the clause ends, similarly to "who". "Who" is basically "which", but for people. "Whom" is the form of "who" used in place of pronouns like him, them.

Next, punctuation. "": Speech marks. Used to indicate the speech of a character. In reporting speech, it is written as: He said, "I'm going to go now." ': Apostrophe. Used to connect two words or to indicate possession. Examples (connection): I'm, it's, he'll, she'll, they'll, they're, she's, he's. (possession): Marina's diamonds, Zoro's booze. .: Full stop: added at the end of a sentence. Example: That's pretty interesting. ?: Question mark. Added at the end of a question. Example: What are you talking about? !: Exclamation mark. Added at the end of something said in excitement, panic, of extreme rage. Example: Holy shit! :- Colon. Used to connect two or more sentences which are fully related to each other. Example: Punishable offenses include but aren't limited to: feeding the birds. ;- Semicolon. Used to connect two sentences which are closely related, but not fully related. Example: I didn't eat anything today; I'm hungry! ,: Comma. Used to indicate a pause in a sentence, list, etc. Example: When I was fishing with him, I found a shiny, green rock. -: Hyphen. Used to connect two words. Example: like-minded. —: Em dash. Used to add emphasis or an additional point. Example: You would think that someone as strong as him would also have common sense, but no — he lacks even an iota of it!

Your VS You're VS Yours Your: Your hat is missing. You're (You are): You're so cool! Yours: Are those keys yours?

They're VS Their VS there There: The hat there looks like yours. Their: Their cat is extremely grumpy. They're (They are): They're fixing your car.

REMEMBER: Whenever you start a sentence, capitalise the first letter. Whenever a name is being mentioned, capitalise the first letter of every separate word in the name. Eg: Sierra P. Harrow. Full stops can also be used to shorten things. Eg: Delhi Public School (D.P.S.). WHOSE is possessive for who.

For tenses, check out: https://character.ai/chat/FgJdGL80usbdONSb_pPHF7YdcjVK9TxPF5W4ehBhLk8