I just read the article titled 睡眠时间男女不同 日本女性很难入睡, and in the article, I read the following sentence:
Then I learned that 处在 is a synonym of 处于, and the meaning of 处于 is "be".
However, there are also many similar words in Mandarin that mean "be" - 是，为，当, etc... (maybe 处在 includes the meaning of "in" in English but still, 是在 seems to work just like 处在). What is the difference of 处在/处于 from these words and in what kind of situation should these words be preferred?
Sorry if my question is obscure, but I would like to know the difference between 处于/处在 and other similar words (e.g. 是，为，当), not the difference between 处于 and 处在.