Translation:My brother goes to a lot of concerts in the summer.
Agreed, Lonzcat. Here, 'muchos' translates to 'a lot of' and is interchangeable with 'many'. When 'a lot of' is put before 'concerts', it's quantifying how many concerts he went to.
If 'a lot' is added at the end of the sentence, it becomes an adverb modifying 'went' (he went a lot).
The translation is 'a lot of' which means 'a large amount' and quantifies the noun (in this case, concerts). It's not the same form as the adverb 'a lot' which means very often/very much and never goes before a noun.
Although por la mañana is pretty common, you don't see por el verano very much. And there's actually a reason for that! It's because there really is a difference between en and por.
En is used to punctuate the period. You might start work at 5am en la mañana. You may have various meetings en la tarde or see several concerts en el verano.
Por is more encompassing. We generally sleep at night, but really through the whole night---so it's por la noche. Does he have to work tomorrow? Yes, por la tarde---the activity is assumed to take much of the afternoon. If you have a summer job, you work por el verano. Spending this winter down south? You'll be going there por (for/throughout) el invierno.
But you don't go to many concerts for the summer---so por would be wrong here.
Por is often used with ir---to suggest active motion. Driving through a city or passing by someone's house or walking along a beach.
However here it's just in a space of time, and en is the better choice.
As I said earlier in this post, por el verano means throughout the summer---but really more of a single event lasting all summer.
This is a user forum, so the people that read the comments here won't be able to help with that.
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That would be 'mucho' instead of 'muchos'. They are similar words but have different meanings and belong in different word classes. 'A lot' is the same, it has two meanings (and can translate to either word depending on the context/content).
'A lot' in the example sentence's translation is a pronoun meaning many/a large number and is a translation of 'muchos', whereas in your sentence, it is an adverb meaning often/much and is a translation of 'mucho'.
'Muchos' quantifies the amount (how many concerts), 'mucho' modifies the verb (how often he went).
It's really just a matter of emphasis. The original sentence emphasizes the number of concerts he goes to, while yours stresses how often he goes. You might choose one or the other, depending on the context. In any case, it's always a good idea to remain as close as possible to the original sentence if you want to avoid the evil pink screen.
This forum is for learners like yourself. We have no control over Duolingo's content, methods, or technical performance. If you click on Discuss at the top of the page, you will be given a menu (on the right of the screen) that includes Troubleshooting. Don't know whether that will lead to a fix for your issue, but it's worth a try.
Stevie, doubtful. If you're talking about a single specific person, using the masculine form generally means that that person is male. So "mi hermano" should always be translated as "my brother".
Although I have to admit that I have no idea how to talk about nonbinary siblings in traditional Spanish grammar.
According to Span¡shD!ct the only contractions in Spanish are "al" and "del"
Please go here and delete your duplicate post:
I assume you are referring to your answer. We can't see what you wrote. The next time you wonder whether your answer should have been accepted, which seems to be the case here, please show us what you wrote --- cut/paste or screenshot, if possible. Someone will probably be able to see what went wrong.