Why do we use 做 in 我太喜欢和他做朋友了 as "being"? Sentence:


  我太喜欢和他做朋友了


How can we use 做 in this meaning in other sentences?
Where can I read more about it and what is the name of this "rule"?

And what is the meaning of the 了 in this sentence?
做 + identity = be identity

Example:做好人，做首領 (good person and leader are identities)

做 + procedure/action = do procedure

Example: 做大事， 做錯，做工 (great thing, mistake and work involve procedures or action)

the final particle 了 is a modal word for emphasis, if you remove it, the meaning of the sentence would not change, but the tone would be flat

Example sentence: 

"要(做)大人物就要(做)大事" = "to (be) a great man, you need to (do) great thing"


  Why do we use 做 in this sentence as “being”?


朋友 is an identity