他是个固执的人，不轻易改变主意。

Tā shì gè gùzhí de rén, bù qīngyì gǎibiàn zhǔyì.

He is a stubborn person and doesn't change his mind easily.

她是个固执的老师，总是坚持高标准。

Tā shì gè gùzhí de lǎoshī, zǒng shì jiānchí gāobiāozhǔn.

She is a stubborn teacher and always insists on high standards.

我的朋友很固执，从不轻言放弃。

Wǒ de péngyǒu hěn gùzhí, cóng bù qīng yán fàngqì.

My friend is stubborn and never easily gives up.