的, 地 and 得 are three very confusing words. They are used as function words to act as attributive, adverbial or complement, and each of them has a different formula.
Formula of 的: 的 + noun/pronoun
的 is used before a noun or pronoun to modify, restrict, or describe the noun or the pronoun. 的 is an attributive sign and only a noun or pronoun can be used after 的.
Examples:
现在的她是一个老妇人了。 She is an old lady now.
她是个美丽的女孩。 She is very beautiful girl.
他买了一辆很贵的车。 He bought a very expensive car.
选择是相当简单的一个概念，但有一些变体值得我们来讨论。Selection is a pretty simple concept, but there are a couple of basic variants worth discussing.
Formula of 地: Adjective + 地 + verb
Adjective + 地 is an adverbial sign and is used to modify the verb after 地.
Examples:
她悄悄地进入他的房间。 she entered his room quietly.
下一阶段都是a级水平，他需要更刻苦地学习。The next stage is a- level, for which he’ll need to study much harder.
我向公司谈了我的工作经历，并且尽可能老实地回答了他们的问题。I told the company about my work experience and answered their questions as well as I could.
他生气地从床上跳下来，把乐器搁在一边，便开始换穿他最好的一套衣服。He jumped off the bed in a temper, put the instrument away, and started to change into his best suit.
整个晚上大家都兴高彩烈，十分痛快地又吃又喝，并且一个接一个地向他话别。All ate and drank freely and merrily through the evening, and, one by one, each came to say goodbye to him.
Formula of 得 : verb/adjective + 得
得 is used after a verb or an adjective to modify the verb or the adjective. namely acts as a sign of the complement of a predicate.
Examples:
她哭得很伤心。 She cried bitterly.
我看得很清楚。 I saw it clearly.
简单一句话，苏菲亚爱他爱得神魂颠倒了。In a word, Sophia was in love with him to distraction.
你一定注意到了我最近一直忙得不得了。It won’ t have escaped your notice that I’ve been unusually busy recently.
她因为得了欧也妮的欢心，快活得不得了。She was in high spirits at the pleasure she had given Eugenie.