吃透英语课本，提升在校竞争力
pl. 磷虾
Thousands of penguins have already died from a shortage of krill.
数千只企鹅因为磷虾匮乏已经死亡。
Krill are a crucial part of the ocean's food chain.
磷虾是海洋食物链中重要的一环。
