Acá is just a very informal way to say aquí here. Allá is an informal version of allí.
Butterfly Spanish is pretty good but I also like the couple that does "Why Not Spanish" on Youtube.
Se supone que esto es Español España,osea castellano y aun asi traducen algunas cosas con el español latino, entonces algunas personas no saben que significa "carro" por ejemplo, y cuando ponemos coche en vez de carro nos lo pone como mal,podrían solucionar eso,o que hubiera un español castellano y un español latino a parte por separado,sería menos frustrante
Because it does not mean the same. last year means "el año pasado" (el año anterior al actual). the last year is used to refer to "el último año" of a period of time. I lived in France for three years. During the last year... "Viví en Francia durante tres años. Durante el último año ... "
As you probably know, Spanish usually has the adjective after the noun. There are a few exceptions to this, such as to change or add emphasis and particularly with adjectives that indicate number or the order of things, so the last and the next kind of indicate order. I have never heard a Spanish speaker say el pasado año in the 7 years that I have been learning the language. I have just checked with one of my spanish-speaking friends and he says el pasado año is not used. To be fair there are lots of little silly rules with Spanish that can be quite frustrating, take it from me having been learning all this time even now I'm still learning new stupid rules that I didn't know before!
This was part of a Stage Check which probably involves the introduction of past tenses and some of the nuances of Spanish here/there. I answered "We arrive there last year" and got away with a typo correction of "We arrived here last year." I know "llegamos" is ambiguous, but it looks like a DL false positive rather than the usual disputed false negative...