go bad ( pt went ) , pp gone ⇒ 牛奶变质了。 Niúnǎi biànzhì le. → The milk has gone off.
品质
( 品德 ) character
地质
geology
实质
essence ⇒ 这两种现象实质不一样。 Zhè liǎng zhǒng xiànxiàng shízhì bù yīyàng. → These two phenomena are essentially different. ⇒ 改革取得了实质的进展。 Gǎigé qǔdé le shízhì de jìnzhǎn. → The reforms have made substantial headway.
性质
character
本质
essence
杂质
impurity ⇒ 这种米杂质很多。 Zhè zhǒng mǐ zázhì hěn duō. → This rice has a lot of impurities in it.