Spanish language Q&A Forum

Do all numbers ending in 1 and 3 (11, 13, 21, 23, 31, 33) change when before masc sing nouns?  Or just for 1 and 3

Hola

¿Cuál es la forma correcta de escribir la siguiente frase?

Desde que tengo seis años de edad, empecé a hacer varios tipos de ejercicios.

Desde que tenia seis años de edad, empecé a hacer varios tipos de ejercicios.

Gracias de antemano

Level B2: Using desde que / hasta que (since/until) with Spanish indicative and subjunctive (subordinate time clauses)

Why is it not an option to say "en caso de que tengas paladar dulce"?

Son muy populares los siguientes platos:  The following dishes are very important

I am confused as to why this sentence is ordered in this way. Why does Los siguientes platos precede son muy populares?

thanks 

I just took one of the B1 quizes and I got this one wrong:

La había comprado para sus padres. ________ la había comprado. (He'd bought it for his parents. He'd bought it for them.)

It says the answer is "Se la habia comprado." I put "Por ellos, la había comprado."

Is it ever correct to "por" whoever, instead of "se"?

It sounds more natural to me to say "La había comprado por ellos," rather than "Se lo había comprado." It also seems clearer because "ellos" is specific (them), where as "se" could be you, him, them...

Is that wrong? Less common? Common only in certain countries or situations?

In this sentence: “La mayoría de sus calles no tienen nombre.”

If the sentence means “the majority of its streets don’t have names”, why is nombre singular and not plural?

If the sentence means : “the majority of its streets don’t have a name”, why is the indefinite article “un” not used for “a”?