The preposition 作为
The preposition 作为 
indicates someone’s social status or an object’s features. This preposition is used to form the following phrases: "as a teacher" and "as a gift".
indicates someone’s social status or an object’s features. This preposition is used to form the following phrases: "as a teacher" and "as a gift".
It is placed before a noun or a phrase.
Pay attention
The subject can either be placed before 作为 or in the second part of the sentence after the comma.
Examples
作为学生，你应该听老师的话
As a student, you should listen to your teacher
zuòwéi xuéshēng, nǐ yīnggāi tīng lǎoshī de huà
哥哥想买那座楼作为投资
My brother wants to buy that building as an investment
gēgē xiǎng mǎi nà zuò lóu zuòwéi tóuzī
中国作为人口最多的国家之一，很难为人们提供就业机会
As one of the most populous countries, China has had difficulty with providing people with employment opportunities
zhōngguó zuòwéi rénkǒu zuì duō de guójiā zhī yī, hěn nán wéi rénmen tígōng jiùyè jīhuì
Pay attention
If 作为 is placed at the beginning of a sentence, 作为+noun/phrase is separated by a comma.