惜 (xī) is a verb meaning "to cherish," "to treasure," or "to feel reluctant to part with." It is often used in literary and poetic contexts. Common compounds include 可惜 (unfortunately) and 珍惜 (to treasure).
我们要珍惜眼前的幸福生活。
wǒmen yào zhēnxī yǎnqián de xìngfú shēnghuó.
We should cherish the happy life we have before us.
时间一去不回,你要学会惜时。
shíjiān yí qù bù huí, nǐ yào xuéhuì xī shí.
Time once gone never returns, you must learn to cherish it.
太可惜了,这么好的机会你错过了。
tài kěxī le, zhème hǎo de jīhuì nǐ cuòguò le.
What a pity, you missed such a great opportunity.