他用一面凸透镜把阳光在纸上聚成焦点。 He focused the sun's ray on a piece of paper with a burning-glass.
请写在这张纸的一面上。 Please write on one side of the paper only.
先把肉的一面烤好，然後翻过来烤另一面。 Brown the meat on one side, then turn it (over) and brown the other side.
笼，栏一种用于限制鸟类或动物的结构，至少有一面由绳子或条子组成的栅栏构成，供空气和光亮进入 A structure for confining birds or animals, enclosed on at least one side by a grating of wires or bars that lets in air and light.
