Forum:Stardust dragon/assault mode continuous

Hello. Me and my friend are having an argument about stardust dragon/assault mode's effect. on the card it says (quote) "You can Tribute this card to negate the activation of a Spell Card, Trap Card, or Effect Monster's effect, and destroy that card." He says you can use stardust dragon/assault mode's effect when you activate the effect of a continuous spell or trap card because he thinks the secont "effect" in the word "effect monster's effect" applies for the spell and trap cards as well. I dissagree because at the end it clearly has a   'S   stating that that word has posession of the next word, also if it did also apply for spell and trap cards, the word "effect" would be pluralized (which it is clearly not) because it would be talking about more then 1 object. Please clarify this for me