n.凹面,成凹形
adj.凹的
vt.使成凹形
The palm of one's hand is slightly concave.
人的手掌是微凹的.
The graph of a concave function is always below its tangent.
一个凹函数的图象总在它的切线的下方.
The cloven hooves are sharp edged , elastic and concave.
蹄锋利,呈凹形, 富有弹性.