的, 得 or 地

Chinese has three particles that are all pronounced de. The words around the gap tell you which one to write.

• 的 links a describing word or phrase to a noun: 我妈妈做的蛋糕 (the cake my mother made), 我最好的朋友 (my best friend).
• 得 comes right after a verb or adjective and says how well something is done or how strong it is: 他跑得很快 (he runs fast), 我累得不想说话 (I'm so tired I don't want to talk). If the verb has an object, say the verb twice: 他唱歌唱得很好听.
• 地 turns a word into an adverb that says how an action is done, so a verb comes after it: 慢慢地走 (walk slowly), 认真地听 (listen carefully).

Quick test: look at what comes right after the gap. A noun means 的, a verb means 地, and a comment on how or how much (很快, 太早了, 不想说话) means 得.