The Memrise course "Russian grammar through sentences translates "This is my car" as "Это моя машина." I don't understand why we don't use the feminine Эта in this sentence.
Translate.Ru translates Эта моя машина as "this my car."
Which version is correct? Is there a difference in meaning and usage?
Thanks in advance.
Think of "Это" in "Это моя машина" like being "This is" in "This is my car". That is a "pure pointer". There's no need to change the gender here.
Yet consider "This car is mine" --> "Эта машина - моя". Here "This" applies to "Car" not to "Is" and so in Russian you need "Эта" not "Это".
Regarding your phrase "Эта моя машина". It seems to have a little meaning since "эта" must match some feminine noun. Thus the sentence may mean either "Эта [хреновина] - моя машина" (This [piece of shit] is my car) or "Эта моя машина - [что-то с чем-то]" (That my car is [really something]). In any case you missed something.
To summarize: "Это машина" --> "This is a car"; "Эта машина" --> "This car is". The gender shows which object the word "Это" applies to.
There is a related question here, “Они братья” but “Это упражнения” - why different pronouns?, see my answer there.
In Russian, the English construction this is / these are are always rendered as это irrespective of the gender and number of the thing named, the same goes about it is / they are, if the thing named is non-living:
This is my car. – Это моя машина. (Feminine)
This is my house. – Это мой дом. (Masculine)
This is my window. – Это моё окно. (Neuter)
These are my cars / houses / windows. – Это мои машины / дома / окна. (Plural)
Это inflects according to the gender, number, and case of the following noun only when it is an attribute to that following noun and forms a noun phrase with it:
This car – Эта машина (Feminine)
This house – Этот дом (Masculine)
This window – Это окно. (Neuter)
These cars / houses / windows – Эти машины / дома / окна. (Plural)
But note, these latter are noun phrases, they can function only as elliptical sentences or as parts of a longer complete sentence.
I looked the Memrise course. There's the biggest problem with idiomatic translation. While appreciating the efforts, I think it is not the best way of reducing the pressure of work during language learning.
With idiomatic translation only, we lost the morphological patterns of a language.
Returning to the question. Let's us take the past tense.
this was my home | - original phrase это.N быть.N.PST мой.INS дом.INS | - vocab. forms with grammatical labels это было моим домом | - morpheme-by-morpheme glosses "вот здесь был мой дом" | - idiomatic translation this was my case это было моим случаем "так было и со мной" this was my fault это.N быть.N.PST мой.F.INS ошибка.INS это было моей ошибкой "это было моей ошибкой" this was my car (after an accident) это было моей машиной "это было моей машиной"
see The Leipzig Glossing Rules for List of standard abbreviations.
Let us move the switch of tenses to the position "Now". The rest grammatical rockers-levers we keep as they were.
this is my car это есть моей машиной "вот это моя машина" or "вот моя машина" or "это — моя машина" it is my car оно есть моей машиной "это моя машина"
What you are trying to say is
эта моя машина the my car "this car"
"Эта моя машина" literally translates as 'this/that car of mine' (like in the song title by Beach Boys) and doesn't make a complete sentence. In Russian it is mainly possible to say so in a situation of resuming an interrupted narrative with the teller's car already mentioned before. Then "эта" functions as a reminder of that car (эта ~ упомянутая мной) :
"Эта моя машина" = "This my car" is ungrammatical or incomplete sentence, both in Russian and English. It requires a continuation (what is with your car). Also it means you have several cars and want to speak about one of them.
The difference is in stress:
This is my car - "Это моя машина".
This car is mine - "Эта моя машина". Usually we say: "эта машина - моя".
