I'm having a hard time wrapping my head around relative clauses for some reason. I can generally recognize them in the languages I know, but there are some instances in Portuguese where I can't tell if the clause I'm looking at is relative or not. In Portuguese, Como is sometimes used as a relative clause marker, as in the phrase O jeito como ele fala, but what about the phrase Vê bem como são frágeis estas rosas? I know the meaning of the phrase (Look how fragile these roses are), but for some reason, I can't tell if it's relative or not.
Is there a "test" of some sort that I can do on relative clauses to see if they're really relative?