传说中那个不会哭泣的婴儿是个被精灵调包的换生灵。

Legend says the baby who never cried was a ___changeling swapped by the elves.

他的想法总是变来变去，就像一个善变的精灵，从不在一个念头上停留太久。

His ideas keep shifting like a ___changeling, never settling on one thought for long.