There are several types of Continuous Spell and Trap effects including:
Upon Activation (Call of the Haunted)
Continuous Effects (The A. Forces)
Similar to Ignition Monster Effects, some Spell Cards have an Ignition-like Effect which requires a manual activation by the card's controller during their Main Phase 1 or 2.
Activating the card "Fusion Gate" (placement onto the field or flip face-up) does not Special Summon monsters, so at that time, neither "Royal Oppression" nor "Solemn Warning" can be activated as a response.
Activating the Ignition-like Effect is not considered to be activating a card, so if you then activate the Ignition-like effect of "Fusion Gate", "Royal Oppression" can be used to negate the effect, but "Solemn Warning" cannot. This is because the effect of "Royal Oppression" states that it can negate the activation of effects, but "Solemn Warning" can only be used to negate the activation of a card.
Examples of Spell Cards with Ignition-like Effects: "Blaze Accelerator", "Frontline Base, "Fusion Gate", "Call of the Mummy", "Mass Driver", "Ritual of Grace" and "Valhalla, Hall of the Fallen".
When you activate (flip face-up) a Continuous Trap Card that has a Quick-like effect, you can choose to activate that effect; in this case, the Quick-like effect does not create an additional Chain Link. You simply state if you will also activate the effect of the Continuous Trap Card at the same time you activate the card itself. If the Continuous Trap Card is already face-up on the field, you can activate it in a new chain, or chain its effect to another card, similar to Quick Effects of monsters.
Example 1: Player A activates "Stamping Destruction" and selects Player B's face-down "Skull Lair." Player B activates "Skull Lair" and says that she will also activate its effect, removing 4 monsters in her Graveyard from play to destroy Player A's "Luster Dragon."
"Skull Lair" resolves first and destroys "Luster Dragon", then "Stamping Destruction" destroys "Skull Lair."
Example 2: Player A has "Elemental Hero Neos" in Attack Position equipped with "Premature Burial". Player B has "Malevolent Catastrophe" and "Ultimate Offering" Set in his Spell and Trap Card Zone. Player A attacks with "Elemental Hero Neos." Player B activates "Malevolent Catastrophe" and chains "Ultimate Offering". Player B says that he will also activate its effect, and pays 500 Life Points.
"Ultimate Offering" resolves and Player B Normal Summons a monster from his hand. Then "Malevolent Catastrophe" destroys all the Spell and Trap Cards on the field, including "Premature Burial" which also destroys "Elemental Hero Neos."
Example 3: Player A activates "Monster Reborn" and selects a monster in Player B's Graveyard. Player B can activate "Royal Oppression" and also activate its effect to negate "Monster Reborn".
Similar to Trigger Monster Effects, some Spell and Trap Cards have a Trigger-like Effect which activate whenever a certain condition on the Field, the nature of play, or the progress of the turn, is met. These will also follow SEGOC if two or more effects trigger at the same time.
Trigger-like Effects will form a chain, even if it is from a Continuous Spell or Trap Card.
Examples of Spell and Trap Cards with Trigger-like Effects: "Card of Safe Return", "Iron Core of Koa'ki Meiru", "Ordeal of a Traveler", "Soul Absorption" and "Stumbling".