apple of one's eyes不能翻译成“某人眼中的苹果”，真实含义“心肝宝贝，掌上明珠；极真爱之人或物”。

【例句】
Mary is the apple of her grandmother's eyes.
玛丽是她奶奶的掌上明珠。

As the only child in her family, she is the apple of her parents' eyes.
作为家里的独生子女，她是父母的掌上明珠。