Tephra made the sky look dark.

火山灰使得天空变得灰暗。

Tephra covered the entire village.

火山灰覆盖了整个村庄。

Tephra caused severe damage to the crops.

火山灰对农作物造成了严重破坏。

We need to wear masks to avoid inhaling tephra.

我们需要戴口罩以防吸入火山灰。

Scientists are studying the composition of tephra.

科学家们正在研究火山灰的成分。

Significant changes in phytolith assemblages occur at the same depth as four major tephra. indicating a sharp decline in trees and shrubs and a surge in grass and Cyperaceae.

植硅体组合在4个主要的火山灰层都发生了明显的变化，表现在树木和灌木的急剧下降及禾草类和莎草科的繁盛。