dào li
他在跟孩子们讲热胀冷缩的道理。
tā zài gēn hái zi men jiǎng rè zhàng lěng suō de dào lǐ
He is explaining to the children the principle of thermal expansion and contraction
摆事实，讲道理
bǎi shì shí, jiǎng dào lǐ
Present the facts and reason things out
你的话很有道理，我完全同意。
nǐ de huà hěn yǒu dàolǐ, wǒ wánquán tóngyì.
What you said makes a lot of sense, I completely agree.