hardest

/hɑːrdɪst/

形容词

坚硬的，坚固的
Diamonds are known to be the hardest natural substance on Earth.
钻石被认为是地球上最硬的天然物质。
困难的，费力的
Learning a new language can be one of the hardest challenges a person can take on.
学习一门新语言可能是一个人可以面对的最困难的挑战之一。