Спасибо большое. "Спасибо" is not a noun, and it does not have any gender. But when there is no gender, always use neuter.
Another example: Он сказал своё "нет". - He said his "no".
Thank you, but I am not a teacher. I am just an amateur of linguistics. And I used to teach basics of English to some Russian adults as well. But I work as a software engineer in fact.
Aluette told you right. The genitive of negation is used to express absence of something, for example: "На этом пляже нет спасателя". The same is for "не было" (past) and "не будет" (future).
But you had to write: "Я не спасатель".
As Aluette noted, "I needed to perform" does not necessarily imply you performed it.
Sure! Don't take it personally I just wanted to draw your attention to this fact.
Congratulations then! Not so many mistakes, and it was fully understandable.
OK, maybe it is acceptable. I would say "в общем и в целом". But I checked Yandex:
"в общем и целом" - 2 000 000;
"в общем и в целом" - 2 000.
So, you won
No, you probably got something wrong.
When you refer to people, use "все" /everybody/ (and decline it in all 6 cases as necessary).
But when you refer to things, use "всё" /everything/ (and decline it in all 6 cases as necessary).
Declention of "все": все (Nom), всех (Gen and Acc), всем (Dat), всеми (Inst), (обо) всех (Prep).
Declension of "всё": всё (Nom and Acc), всего (Gen), всему (Dat), всем (Inst), (обо) всём (Prep).
BTW, the original form is "весь" (all) - it is masculine singular. Feminine singular is "вся", neuter singular is "всё" and plural is "все". They are used as adjectives (when accompanied with a noun): весь хлеб, вся вода, всё молоко, все вещи etc.
Neuter singular (всё) can be used independently (without acompanying a noun), and it means "everything" then.
Plural (все) can be used independently (without acompanying a noun), and it means "everybody" then.
A popular expession (they often use it in newspaper titles etc.) is "все и всё" (everything and everybody). It is a nice example when spelling of "е" and "ё" really matters. But many newspapers still prefer not using "ё", and this expession turns to "все и все"
There are different opinions about using "ё" in Russia (if it should be mandatory in writing or not). But personally, I hate the idea of substituting "ё" with "е". I always write "ё" when necessary (not only in Masterrussian).