vitamin A
vitamin-a的词性：
n.（名词）
1. A fat-soluble vitamin or a mixture of vitamins, especially vitamin A1 or a mixture of vitamins A 1 and A 2, occurring principally in fish-liver oils, milk, and some yellow and dark green vegetables, and functioning in normal cell growth and development. Its deficiency causes hardening and roughening of the skin, night blindness, and degeneration of mucous membranes. Also called retinol
维生素A：一种脂溶性维生素或维生素的混合物，尤指维生素A1或维生素A 1和A 2混合物，主要存在于鱼肝油、牛奶和一些黄色和深绿色的蔬菜中，其功能是促进细胞的正常生长和发育。缺乏此维生素将导致皮肤变粗变硬、夜盲及干眼病 也作 retinol