Forum:Please answer!!

here is my question: in my spellcaster deck, I have a card named sorcerer of dark magic. well, it's effect says 'This card cannot be Normal Summoned or Set. This card cannot be Special Summoned except by offering 2 Level 6 or higher Spellcaster-Type monsters on your side of the field as Tributes. As long as this card remains face-up on the field, you can negate the activation of Trap Cards, and destroy them.' here is question: it's trap-part says: negate the ACTIVATION and DESTROY THEM... well, my question is, can this card negate the effect of trap cards that already are played before the special summon of this card? then it's effect will be the same as in the movie (besides the spellcaster-graveyard thing)... here's my second question. the mask of restrict card, it's effect says: Neither player can Tribute any monster under any conditions. so does this mean that when the opponent summons a monster, I can activate this card and he cannot summon?