水龙头没关好，会浪费很多水。

Shuǐlóngtóu méi guānhǎo, huì làngfèi hěn duō shuǐ.

If the tap is not turned off properly, it will waste a lot of water.

我不能再浪费钱买包包了。

Wǒ bù néng zài làngfèi qián mǎi bāobāo le.

I can't waste any more money buying bags.

吃不完的饭不要浪费，可以打包带走。

Chī bu wán de fàn búyào làngfèi, kěyǐ dǎbāo dàizǒu.

Don't waste food you can't finish; you can pack it to take away.