在零下20度的天气里，他的耳朵因冻伤变得又红又肿。

In minus 20-degree weather, his ears got red and swollen from ___frostbite.

在北极探险时，他的手指因为严寒而冻伤了。

During the Arctic expedition, he suffered from ___frostbite on his fingers due to the extreme cold.