using "auch"

just my take but i think it's a lose translation. You see in German it would be structured as it was written:

[color=#000080:2x75l5zi]Manchmal, wenn es geregnet hat, haben wir uns auch verkleidet[/color:2x75l5zi]

but you can't always translate directly from one language to another and there are always going to be variations of how things are said and how they can be arranged.

so in English the person who translated it for MRG used this line (which is grammatically incorrect):

[color=#000080:2x75l5zi]Sometimes, when it was raining we would play dressing up[/color:2x75l5zi]
it's grammatically incorrect because in English it would just be "dress up" not "dressing up" that sounds weird.

but..... if you take the line before and and put it together with this line then you can see where in English the "auch" would fit in:

German:
[color=#000080:2x75l5zi]Meine Schwester und ich haben den ganzen Tag lang zusammen Verstecken gespielt und Schokolade genascht. Manchmal, wenn es geregnet hat, haben wir uns auch verkleidet.[/color:2x75l5zi]

English:
[color=#000080:2x75l5zi]My sister and I played hide and seek all day long and ate chocolate. Sometimes, when it was raining we would play dressing up.[/color:2x75l5zi]

in English you could structure these sentences in a number of ways it could be 1 sentence just by adding the word and between the end of the first and the beginning of the 2nd sentences. but i think more importantly is where Also "auch" fits into the sentence which would be more like this:

[color=#000080:2x75l5zi]My sister and I played hide and seek all day long and ate chocolate. Sometimes, when it was raining we would [also][/color:2x75l5zi] play dressing up.

because of the sentence structure in English you don't actually need to place "Also" in that sentence because it would read the same either way and it's already assumed that it's an added "list item" continuing from the previous sentence (because he is listing things he used to do with his sister ie. played hide and seek, ate chocolate, and when it was raining played dress up). <--- which is another way it could have been written in English.

there are always a couple of things to take into consideration when learning a new language: the person who translated it, both languages structure, and how it is spoken in real life just to name a few.

i think if you look at the other places were "auch" seems randonly thrown but isn't in the English translation you'll find this to be similar for those examples.

hope that helps some. as for the German side of things you'll have to wait Nathalie to give you a better understanding of the German structure.