Here's a breakdown of the different scenarios:
1. "During this turn" effects:
* Yes, you can attack: If a card's effect states something like "During this turn, this card gains 500 ATK," you can activate the effect and then attack in the same turn.
* Example: "Blue-Eyes White Dragon" can gain ATK through its effect and then attack in the same turn.
2. "This turn" effects:
* May or may not be able to attack: If a card's effect states something like "This turn, this card cannot attack," you cannot attack with that card even if you activate its effect in the same turn.
* Example: "Effect Veiler" prevents a monster from attacking this turn, even if its effect is activated in the same turn.
3. Effects with specific timing:
* Follow the timing: Some cards have effects that must be activated during specific times, such as during the Standby Phase or the End Phase. These cards cannot attack in the same turn they activate their effects.
* Example: "Sangan" can only be Special Summoned during the Standby Phase, so you can't attack with it immediately after summoning it.
4. Effects that specifically mention attacking:
* Follow the wording: Some effects specifically grant the ability to attack, while others might restrict attacking. Pay close attention to the wording of the effect.
* Example: "Chaos Emperor Dragon - Envoy of the End" can attack directly when its effect is activated, even though the card states it can't attack directly normally.
Key Points to Remember:
* Read the card text carefully: Always check the card's text for specific wording and timing restrictions.
* Consider the effect's timing: Effects can trigger at different times, so be aware of when you can activate them.
* Don't forget card interactions: Other cards on the field can also affect your ability to attack.
If you're ever unsure, it's best to consult the official Yu-Gi-Oh! rulebook or ask a fellow duelist for clarification.