听说吃黑巧克力对心脏好。

Tīngshuō chī hēi qiǎokèlì duì xīnzàng hǎo.

I heard that eating dark chocolate is good for the heart.

心脏是人体最重要的器官之一。

xīnzàng shì réntǐ zuì zhòngyào de qìguān zhī yī.

The heart is one of the most important organs in the human body.

他的心脏跳得很快。

tā de xīnzàng tiào de hěn kuài.

His heart is beating fast.