英语语法分析

Some milkweeds have a higher concentration of chemicals called cardenolides, which make the butterflies toxic to predators.

一些乳草属植物含有一种高浓度的化学物质，叫做强心苷(也叫卡烯内酯)，这种东西使得蝴蝶对那些食肉动物来说成了有毒食物。

Monarch caterpillars feed on any of dozens of species of milkweed plants, including some species that contain high levels of cardenolides.

帝王蝶的幼虫以很多乳草属植物为食，包括一些包含高水平强心甾的类型。