Several structures, not parts of the eyeball, contribute to the protection of the eye. The most important of these are the eyelids, two folds of skin and tissue, upper and lower, that can be closed by means of muscles to form a protective covering over the eyeball against excessive light and mechanical injury. The eyelashes, a fringe of short hairs growing on the edge of either eyelid, act as a screen to keep dust particles and insects out of the eyes when the eyelids are partly closed. Inside the eyelids is a thin protective membrane, the conjunctiva, which doubles over to cover the visible sclera. Each eye also has a tear gland, situated at the outside corner of the eye. The salty secretion of these glands lubricates the forward part of the eyeball when the eyelids are closed and flushes away any small dust particles or other foreign matter on the surface of the eye.
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- eyelid [ˈailid] n.眼睑
- fold [fəuld] n. 层
- excessive [ikˈsesiv] adj.过度的, 过分的
- injury [ˈindʒəri] n.伤害
- eyelash [ˈailæʃ] n.睫毛
- fringe [frindʒ] n. (地毯等的)穗，须边，流苏
- conjunctiva [ˌkɔndʒʌŋkˈtaivə] n.(眼球)结膜
- tear gland [tiə - ɡlænd] n. 泪腺
- lubricate [ˈlu:brikeit] v.加油润滑
- flush [flʌʃ] v. 冲掉
- particle [ˈpɑ:tikl] n.微粒
