spread是哪個單詞的過去式

Prompt action was required as the fire spread.

由於火勢蔓延，須要立即採取行動。

The clouds had spread and covered the entire sky.

烏雲鋪開，遮蔽了整個天空。

Fire spread rapidly after a chemical truck exploded.

一輛裝有化學品的卡車爆炸後火勢迅速蔓延開來。