"Apple of one’s eye" means a person, or thing, is precious, or loved deeply."Apple of one’s eye"的意思是某人或某事很珍贵，深受别人喜爱。
This phrase comes from long ago when people believed that the eye's pupil was solid and shaped like an apple.
这个短语很久之前就有了，那时人们相信瞳孔是立体的、形状像苹果一样。
And of course, the pupil was precious, because you can't see without it.
当然，瞳孔很珍贵，因为没有它，你什么也看不到。
对话举例：
A：Jack is a great dad. He is so attached to his daughter he would do anything for her.
杰克真是个好爸爸，他非常爱他的女儿，愿意为她做任何事情。
B：Wow, you are right about that. She sure is the "apple of his eye"!
喔，没错。她可是他的心肝宝贝。
重要词汇：
precious ['preʃəs] adj. 宝贵的; 珍贵的
pupil ['pjuːpɪl] n. 瞳孔
切记：
如果你想加入有外国人、大学生的微信群（英语角）练口语，关注微信公众号“竖起耳朵听”即可加入，那里会美音、伦敦腔、印度腔的小伙伴都有。