截水

万智牌机制

要支付截水费用，你总是可以直接支付所需的法术力。但是，对于该费用中的每个{1}，你可以横置一个由你操控的未横置的神器或生物，来替代支付该点法术力。如果你选择横置一个生物来帮助支付截水费用，它也可以是本回合刚进入你操控下的生物。

截水 Rules

A keyword action. “Waterbend [cost]” means to pay that cost and, for each {1} in that cost, you may tap an untapped artifact or creature you control rather than pay mana. See rule 701.67, “Waterbend.”

701.67a: “Waterbend [cost]” means “Pay [cost]. For each generic mana in that cost, you may tap an untapped artifact or creature you control rather than pay that mana.”
701.67b: If a waterbend cost is part of the total cost to cast a spell or activate an ability (usually because the waterbend cost itself is an additional cost), the alternate method to pay for mana described in rule 701.67a may be used only to pay for the amount of generic mana in the waterbend cost, even if the total cost to cast that spell or activate that ability includes other generic mana components.
701.67c: An ability that triggers whenever a player waterbends triggers whenever that player pays a waterbend cost, regardless of how they paid that cost.