This is a rule:
You must change "il est un, elle est une" to "c'est un/une", and "ils sont des, elles sont des" to "ce sont des".
In French, "c'est" (sing.) and "ce sont" (plural) are used when a pronoun (it, she, he, they) is the subject of the verb "être" and followed by a modified noun ie determiner + noun.
- it is a dog = c'est un chien
- she is my friend = c'est mon ami(e)
- he is the man I met yesterday = c'est l'homme que j'ai rencontré hier
- they are 2 nice girls = ce sont 2 gentilles filles
A modified noun is a noun preceded by a determiner:
- an article: un, une, des, le, la, les
- a number: un, deux, trois
- a possessive adjective: mon, ma, mes, ton, ta, tes, son, sa, ses, notre, nos, votre, vos, leur, leurs
- a demonstrative adjective: ce, cet, cette, ces
- an indefinite adjective: certains, quelques
Sitesurf, I am so excited that this information is part of this lesson 5 practice! I know that you have given this information many times. I have also written it down a few times. I wish I had been offered the opportunity to learn from you and the Duolingo team before I am the age that I am now. I will keep working to understand your beautiful language. Thank you for your kind patience :-)
"Être" (to be) and "avoir" (to have) are verbs which are also used as auxiliaries in compound tenses and verb forms.
Most of the time, "être" is used to describe someone or something and "avoir" to express possession.
However, there are a number of cases where "to be" does not translate to/from "être" nor "to have" to/from "avoir" because these verbs are used in a large variety of idiomatic expressions.
In this unit, you are learning the specific use of "c'est" or "ce sont", when the English sentence has "he/she/it is" or "they are", respectively.
If you have specific questions about the sentence at the top of the page, please ask. Yet, please first read the whole thread to get explanations on various questions other users have asked.
You are right - "filles" can translate as either "girls" or "daughters" depending on the circumstances.
We should consider "girls" as the main translation and use "daughters" only when something about the sentence suggests that "daughters" is intended. The most common clue is the use of a possessive adjective.
"La fille" = "the girl"
"Ma fille" = "my daughter".
The same works for "femme" where the same issue arises because "femme" can translate as either "woman" or "wife". So again consider "woman" as the main translation unless there is a possessive adjective or some other clue in the sentence that indicates that "wife" is intended.
Another point about your suggestion - again you are absolutely right that "des" can usually be translated as "some" but in this particular case "they are some girls/daughters" gives a slightly different meaning - it suggests "WOW! They are some girls" - there is something special about them - not just that they are girls.
So probably best to use "They are girls" as the translation.
"ce" can be an adjective or a pronoun.
as an adjective, it can mean 'this' or 'that' in front of a masculine noun starting with a consonant sound: ce livre, ce chien...
as a pronoun, it is used as the subject of the verb "être" (and more rarely with "pouvoir"), in singular with "c'est" and in plural with "ce sont".
Depending on what follows, "c'est" can be used to translate various pronouns:
- this is green, that is green = c'est vert, ceci est vert, cela est vert
- he is a brave soldier = c'est un brave soldat (not il est)
- she is my sister's friend = c'est l'ami(e) de ma soeur (not elle est)
- it is my dog, this/that is my dog = c'est mon chien (not il est)
- they are girls = ce sont des filles (not elles sont)
When "they are" is followed by a modified noun, you have to change it to "ce sont".
A modified noun is a noun preceded by a determiner: article, possessive or demonstrative adjective, indefinite adjective or number.
- They are girls = Ce sont des filles.
- They are the girls I know = Ce sont les filles que je connais.
- They are these girls who are taking the exam = Ce sont ces filles qui passent l'examen.
- They are his daughters = Ce sont ses filles.
- They are two/a few girls from the school = Ce sont deux/quelques filles de l'école.
Otherwise, you keep the personal pronoun "ils" or "elles".
- They are nice (adjective) = Ils sont gentils / Elles sont gentilles.
- They are at the station (location) = Ils/Elles sont à la gare.
- They are mine (possessive pronoun) = Ils/Elles sont à moi.