Thanks a lot, Sandra!)

Hello Ivan, I am fluent in English and use the language every day, due to where I live. However, please note that I am not a native speaker. Still, I hope the below helps: 1) I insist that his dog gets off my lawn immediately. (Note: To my understanding “backing off / back off” is reserved for people in the English language. It means “get off my case” or “get away from me”). 2) If you wouldn’t have backed me up, I would have been in big trouble. Therefore, I truly appreciate what you have done for me. (Please note that your original sentence “So I don’t even know how I can express my gratitude.” is grammatically correct. I personally just have heard the above used more commonly.) 3) Your sentence is correct as is. 4) He makes too much of a fuss to go camping for a several days in a row. (Note: Picky is to my knowledge mostly used in reference with food or objects; not for situations. Example: She is a picky eater (very choosy on what she likes). He is particular picky about how the laundry is folded (it must be done in a certain way). So, I feel like “fuss” works better with camping. Honestly, my friends would probably say “He is too much of an indoor-person to go camping” or “He is not much of a nature-person”. But I don’t think either responses would count as “correct” on an English test.) 5) I felt very aggravated after coming home from work, so I asked that no one bother me until tomorrow. (Note: Annoyed would also be more commonly used, to describe how you felt coming home from work. I have come across the wording “exasperation” mostly when one person describes how another person expresses their feeling. I haven’t heard it being used by somebody describing themselves feeling this.). 6) Your sentence is correct as is. 7) Your sentence is correct as is.

En español no se entiende lo escrito.