A hinge is a piece of metal, wood, or plastic that is used to join a door to its frame or to join two things together so that one of them can swing freely. 折叶
noun [专属名词]铰链,合叶;枢纽,关键;铰合部
The top swung open on well-oiled hinges. 盖子在上好油的折叶上一下子弹开了。
verb [vt. 及物动词]给(某物)装铰链
By varying the width of the black lines, or hinges, researchers are able to change how far each hinge folds. 通过改变黑色线条或者铰链的宽度,研究员可以改变每条铰链可以折叠的范围。