Spanish language Q&A Forum

In the third sentence, would it be correct to say:  "Mi mejor amiga se apunta rápidamente a estos programas."?  Does it take something away from the meaning by saying it the way I wrote it?

In the fourth sentence, would the sentence be correct if I eliminate "son las que"?

I'm not trying to take anything away from the "style" of the writing or from the grammatical importance of the use of these relative pronouns, but I just want to know if the use of these relative pronouns is more about a certain style of writing or if they are grammatically necessary.

Thank you.

Amy

Why is the translation la llegada de la primavera? 

Why do I need a definite article in front of primavera?

I don't hear the S at the end of nuestros when the speaker says nuestroS recuerdos. Am I just failing to hear it, or is it in fact silent?

Apropos of ' "Lo que" vs "la cosa que" ',   I sometimes see "cosa que" used to mean "which", as in 

    Querían detenerme por robo, cosa que no hice.

Is this usage correct?   If so, is there a lesson that discusses it?

More examples here:  

    https://context.reverso.net/translation/spanish-english/%2C+cosa+que

Thanks!

Now everywhere I look online it suggests that this should only say 'lo dejé' and not 'me lo dejé'. Why would they add 'me'? It doesn't feel like it needs it, as the 'I forgot' bit is understood by dejé, and the 'it' by lo. It isn't reflexive I don't think. 

Thanks!