infernally

The advanced math problem was infernally difficult, and nobody in the class could solve it.

(Chinese) 这道高等数学题难得要命，班里没一个人能解出来。

It was an infernally hot day, so we decided to stay inside with the air conditioning on.

(Chinese) 那天天气热得邪乎，所以我们决定待在室内开着空调。