The English idiom（ ）means "something that spoils the perfection

The English idiom（ ）means "something that spoils the perfection of something."
A、white elephant
B、flesh and blood
C、an apple of discord
D、​fly in the ointment
【正确答案】：D
【题目解析】：本题主要考查名词性习语。fly in the ointment意为美中不足/一粒老鼠屎坏了一锅汤；white elephant意为无价值的东西/琐碎的；flesh and blood意为血肉之躯；an apple of discord意为祸因/争端之源。答案为D。