"Which children do you help?"
Translation:Quels enfants aides-tu ?
Quels here is an interrogative adjective. It asks "what" or "which" and as an adjective, it agrees in number and gender with the noun that follows it.
which children → quels enfants
what book → quel livre
which soup → quelle soupe
which houses → quelles maisons
Lequel (and variants) is a pronoun that replaces a noun. It means which one(s)?
quels enfants ? → les + quels = lesquels ? (plural and masculine)
quel livre ? → le + quel = lequel ? (singular and masculine)
quelle soupe ? → la + quelle = laquelle ? (singular and feminine)
quelles maisons ? → les + quelles = lesquelles ? (plural and feminine)
quels enfants aides-tu not accepted 28 Mar 2018. Reported.
This seems to be a pattern with new exercises. I have encountered this issue on other exercises which are apparently new because they only a few comments. I wonder what's going on there. Surely it must occur to the developers that both the tu and vous versions are correct, but I guess not.
I think the difference is basically; quel = which; lequel = which of these
In English we just use "which" for both, but in French the meanings are split.
So quel is an adjective which has to modify a specific noun (e.g. "which duck?", "which apple").
Lequel is a pronoun you use when the noun can be inferred or has already been specified (e.g. "There are three ducks, which is red?" "I have two apples, which of them do you want?").
To translate from French, you can just translate both as "which".
To translate from English to French, you'll have to work out which use of which is which.
Because it is incorrect.
The interrogative adjective quel(les) is followed by the noun, no preposition. Should be quels enfants.
Qui is a pronoun that replaces a noun. You have two pronouns next to each other (qui vous). Qui will be followed directly by a verb, but it isn't needed in this sentence.
When you start a question with quel(les) you must invert the noun and verb with a tiret. aidez-vous/aides-tu
The best bet is to memorize the indefinite article, un/une, with each new word you learn. Instead of chaise for chair, learn "une chaise". However, there are certain endings that are nearly always masculine and others that are nearly always feminine. Over time you will see the patterns. This link may be helpful: https://forum.duolingo.com/comment/1101225/Noun-genders-in-French