I'm not a native, but I have a good level in English.

Even Brazilian have problems with "SE". I cannot tell you the translation without a sentence. "SE" can be: IF - Se você... If you... Reflexive pronoun - Ele se matou/ Ele matou-se. He killed himsef. Part of passive voice - Vendem-se casas. Houses are sold. (Portuguese has two types of passive voice, this one isn't that common). If you want a correct translation I need the sentence you saw it.

If you want literature I recommend "A Moreninha" by Joaquim Manuel de Macedo 
If you want something new I recommend "Traços" or "A casa 900" (I don't remember the author's names).

Both present perfect and present perfect continuous have the same meaning when you use how long. How long have you studied English? How long have you been studying English? Both sentences are asking information that started in the past and is still happening in the present.

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Quando o objeto vem logo depois usa-se your, quando não vem usa-se yours.
This is your car.
This car is yours.

Because he can lift 500 kg easily, but not 505.