Shéi yán cùn cǎo xīn, bào dé sān chūn huī — mǔ'ài shì yǒngyuǎn bàodá bu wán de.
Who says a blade of grass could repay the spring sun? A mother's love can never be fully repaid.
Měi dào Mǔqīnjié, wǒ dōu xiǎngqǐ 'bào dé sān chūn huī' zhè jù huà.
Every Mother's Day I think of the line 'repay the warmth of spring sunshine.'