harden [ˈhɑ:dn]

以下由轻松背单词网站提供

vt.(使)变硬；(使)变得坚强，(使)变得冷酷；vi.变硬，变坚固；变坚强；变冷酷

to become or make hard

They harden clay by putting it in a fire. 他们把粘土坯放在炉火里使其变硬。
Don't harden your heart against him. 别对他硬心肠。