The usage of the structural pattern“的”is always a difficult language point for students who are studying Chinese. When it should be used and when it can’t be used confuse many students until they reach the intermediate level. So this free Chinese lesson will simply conclude the usage of the structural pattern “的”.
1、the situations that “的” must be used：
（1）when you study Chinese, you will find that the Chinese expression which represents the possessive relation is quite different from the English. “的” must be used in this kind of expression.
For example：“我的书”(wǒ de shū)，you can’t say“我书”； 
“小王的存款”(xiǎo wáng de cún kuǎn)，you can’t say“小王存款”。 
（2）the most common usage in the process of studying Chinese: verb+的+noun 
For example：“说的话”(shuō de huà)、“开展的活动”(kāi zhǎn de huó dòng)、“举的例子”(jǔ de lì zi)。 
（3）adjective with two characters or adjective phrase +的+noun 
For example：“美丽的风景”(měi lì de fēng jǐng)、“干净整齐的房间”(gān jìng zhěng qí de fáng jiān)。 
（4）adverb + adjective with single character+的+noun 
For example：“大房子”(dà fáng zi ) can be transformed into“很大的房子”(hěn dà de fáng zi)， “的”should be used before“房子”.
（5）the usage of “的” with adjective reduplication is also an important language point for students who arestudying Chinese: adjective reduplication+的+noun 
For example：“红红的太阳”(hóng hóng de tài yang)，you can’t say“红红太阳”； 
“绿油油的小草”(lǜ yóu yóu de xiǎo cǎo)，you can’t say“绿油油小草”。 

2、The situations of ellipsis of“的”concluded for students who study Chinese： 
（1）the meaning of the phrase is fixed and the two components are tightly bonded. 
For example：“汉语水平考试”(hàn yǔ shuǐ píng kǎo shì)，you can’t say“汉语水平的考试”； 
“流行音乐”(liú xíng yīn yuè)，you can’t say“流行的音乐”； 
“高楼大厦”(gāo lóu dà shà)，you can’t say“高的楼大的厦”。 
（2） “的” can’t be used behind quantifier phrase. 
For example：“一个苹果”(yí gè píng guǒ)，some students who have studied Chinese for a long time will also make the mistake to say “一个的苹果”, which is quite wrong.
（3） “的” can’t be used behind adjective with single character 
For example：“大箱子”(dà xiāng zi)，you can’t say“大的箱子”
“红花”(hóng huā)，you can’t say“红的花”；
“好朋友”(hǎo péng you)，you can’t say“好的朋友”。 
（4） “的” can’t be used in the expressions which represent the relation between people or the quality of objects. 
For example：“我妈妈”(wǒ mā ma)，you can’t say“我的妈妈”；“他们经理”(tā men jīng lǐ)，you can’t say“他们的经理”； when you study Chinese, you should pay attention to this point, for this is the confusing part for many overseas students.
“木头房子”(mù tou fáng zi)，you can’t say“木头的房子”；“纯棉衬衫”(chún mián chèn shān)，you can’t say“纯棉的衬衫”。 
注意： 
(3) and (4) are the exceptional when the expression has the meaning of emphasis, comparison or classification. 
For example：“大的箱子装东西多，小的箱子装东西少。” (dà de xiāng zi zhuāng dōng xi duō ， xiǎo de xiāng zi zhuāng dōng xi shǎo)
“纯棉的衬衫比化纤的衬衫更舒服”。 (chún mián de chèn shān bǐ huà xiān de chèn shān gèng shū fu)

3、For students who are studying Chinese and want to pass the HSK exam, you should pay know the situations that you can either use or not use “的”: 
generally：adjective with two characters +的+noun， 
but if the relation is tightly bonded, “的” can also be left out. 
For example：“新鲜（的）空气”(xīn xiān （ de ） kōng qì)、
“幸福（的）生活”。 (xìng fú （ de ） shēng huó)

Our free Chinese lesson also provides a practical exercise for you to study Chinese well： 
Add “的” in the place where “的” is needed and delete “的” which is not needed. 
小林的手机 
小林手机不见了，她到处找她手机。她找了她背书包，没找到；她想会不会在她房间里，她找了明亮房间，也没找到；手机不见之前，她在上课，所以，她想起了那间很大教室；她跑进教室，问她的同学有没有看到一个小的手机；胖胖小李告诉她，有一个的手机在外面的高的书架上。小林跑出教室，终于在书架上找到了她手机。 

Key： 
小林的手机不见了，她到处找她的手机。她找了她背的书包，没找到；她想会不会在她的房间里，她找了明亮的房间，也没找到；手机不见之前，她在上课，所以，她想起了那间很大的教室；她跑进教室，问她同学有没有看到一个小手机；胖胖的小李告诉她，有一个手机在外面的高书架上。小林跑出教室，终于在书架上找到了她的手机。