One of the most difficult English phrases for Japanese is …

　I heard that one of the most difficult English phrases for Japanese to understand is “one of the most adjective + plural.” I think this is true because I also confused this phrase. We learn that “the most” means “もっとも(mottomo),” and that the intended thing by “mottomo” should be only one. That is, “mottomo” is including the meaning of “only one.” However, the words “one of + ‘plural'” is attached to “the most.” In view of Japanese, this is inconsistent because “one of” intends multiple things while “the most” intends only one thing. For example, when we read the sentence like “One of the highest mountains is…”, we might wonder the highest mountain is not only one. Therefore, we learn something like “the most” intends things which belong to a superior group in this case. I was already accustomed to the phrase, but some Japanese are not persuaded because the Japanese words corresponding to “one of the most” is unnatural.