健康が何より大切なのは自明のことだ。
It is self-evident that health matters more than anything.
この計画が失敗に終わることは、誰の目にも自明だった。
It was obvious to everyone that this plan would end in failure.
彼は自明な事実をわざわざ長々と説明した。
He went out of his way to explain an obvious fact at length.
その前提は自明ではないので、証明が必要だ。
That premise is not self-evident, so it needs to be proved.