"That" is a pronoun, like "he," or "she," so what would determine it's necessity is whether the antecedent is clear (an antecedent is the noun replaced by the pronoun: "Jon was going to class but he wanted to eat first." Pronoun: "he," Antecedent: "Jon.")
In your sentence, I'm not actually sure what the antecedent is. I think it's what was clear, which would be the clause that follows "that." I don't think you need the word "that" to clarify what you're referencing, and for that reason, I would say leave it out (no need to be unnecessarily wordy).
Sorry I couldn't be more helpful. Good luck.
u thats it
"I criticized Johnny's work. " <-thats how.
Yes you can. For example: What does derelict mean. Thats a sentence.
The detectives had a hard time solving the mystery thats one.
you can ue the word entrace as a verb by saying en trace thats a verb
u could use colonies in a sentence by makin it like a question like sayin what kind of sentence should i write for the word colonies? see thats good
i dont know thats wat i want to know 4 my home work
insufficient means not enough eg. thats an insufficient amount of data u got there
i put a lot of petrol in my car . thats a sentence.
thats a world stump
I'm enthusiastic to search for source of knowledges.
Similitude means... and then just say what it means thats a sentence