这苹果应该是变质了，有奇怪的味道。

Zhè píngguǒ yīnggāi shì biànzhì le, yǒu qíguài de wèidào.

This apple has probably gone bad—it smells strange.

一段感情里，一旦缺乏沟通，就会很容易变质。

Yí duàn gǎnqíng lǐ, yídàn quēfá gōutōng, jiù huì hěn róngyì biànzhì.

In a relationship, once communication is lacking, things can easily turn sour.

鲜奶最好放进冰箱里，要不然很容易变质。

Xiānnǎi zuìhǎo fàng jìn bīngxiāng lǐ, yàobùrán hěn róngyì biànzhì.

Fresh milk is best kept in the fridge; otherwise, it spoils easily.