Hello. I will be extremely grateful for help.

1)Do you think it's possible to say "If I got it right, you received a letter from Mona" (meaning "if I understood correctly")?
2)Is it correct to say "All this happened in summer" or is it "this all"?3)Please help me with the tense: "he studied / had studied / had been studying English all his life and spoke it fluently" (about a person who is no longer alive).
4) Maybe, the verb "learn" is better in the previous sentence?
Thank you very much for your time and help.

"If I got it right" is slangy or colloquial. "If I understood correctly" is better in formal writing. If you are quoting a character as you write fiction, slang is fine, however, if that's the way your character speaks. If you are quoting a real person, you quote it exactly, slang and all.

"All this" or "This all" depends on the context. Neither is wrong.

If the person is deceased, "had studied" is best. He is past tense, so the verb should be, too. And no, the verb learn would not be better in this context.

Hello! I'd be happy to help you with your questions.

1) Regarding your first question, yes, it is possible to say "If I got it right, you received a letter from Mona" to mean "if I understood correctly." It is a common way to express that you believe you have understood something correctly.

2) Both "All this happened in summer" and "This all happened in summer" are grammatically correct. The choice between them depends on the emphasis you want to place. "All this happened in summer" emphasizes that everything you are referring to occurred during the summer. On the other hand, "This all happened in summer" emphasizes that all of the events you are talking about took place in the summer.

3) When referring to someone who is no longer alive, the most appropriate tense would be "He had studied English all his life and spoke it fluently." The past perfect tense ("had studied") is used to indicate an action that was completed before another past action or point in time. In this case, the action of studying English took place before the person's death.

4) Both "studied" and "learned" can be used in the sentence you provided, depending on the exact meaning you want to convey. "Studied" emphasizes the effort put into acquiring knowledge, while "learned" focuses on the acquisition of knowledge itself. Therefore, the sentence "He studied English all his life and spoke it fluently" emphasizes the process of studying, while "He learned English all his life and spoke it fluently" emphasizes the outcome of acquiring fluency.

I hope this clarifies things for you! If you have any more questions, feel free to ask.