想到小时候那种无忧无虑的日子，他就忍不住微笑。

Xiǎngdào xiǎoshíhou nà zhǒng wúyōu wúlǜ de rìzi, tā jiù rěn bu zhù wēixiào.

When he thinks of those carefree days of his childhood, he can’t help but smile.

孩子们在草地上无忧无虑地玩耍。

Háizimen zài cǎodì shàng wúyōu wúlǜ de wánshuǎ.

The children are playing on the grass without a care in the world.

真正的幸福不一定是无忧无虑，而是有能力面对困难。

Zhēnzhèng de xìngfú bù yídìng shì wúyōuwúlǜ, ér shì yǒu nénglì miànduì kùnnan.

True happiness is not necessarily being carefree, but having the ability to face difficulties.