Oxidation is the process in which a substance loses electrons, and reduction is the opposite process in which a substance gains electrons. These processes always occur simultaneously. 「酸化は物質が電子を失うプロセスで、還元は逆に物質が電子を得るプロセスです。これらのプロセスは常に同時に起こります。」
例文です。 He dreamed of living a self-sufficient life, but he also understood that complete self-sufficiency would be difficult. 「彼は自給自足の生活を夢見ていたが、完全な自給自足が困難なことも理解していた。」