Se puede nadar en este lago.
It is an impersonal sentence because it has no subject. This case is used "<u>se</u>", it is when we want to talk about the subject.
<h3><em><u>MissSpanish</u></em></h3>
I don't really remember, but i think it's que te hablar por telefono?
<span>What are the advantages and disadvantages of a temporary construction?</span>
Theory of Evolution studied by Charles Darwin who observed finch beaks and how they differed