KNOW that you have the mental ability to do well.

你要明白你有能力去做好。

But teens have the mental ability to be self-aware.

但青少年有自我意识的心智能力。

Obesity lowers mental ability? I never heard that.

肥胖会损伤智力？我从来没听说过。

All humans have some kind of innate mental ability.

所有人都具备某种天生的智力。

The power to learn or retain knowledge; mental ability.

学习能力，心智能力学习或吸取知识的能力；大脑的智力。