in my opinion,"ke neng" and "ye xu" have the same meaning--perhaps.it is a guess. it is equal to "may "and "perhaps" in meaning, i think.

"ke neng" or "ye xu ba" mean guess sth. if you are not sure about sth,you can say that. in my opioion,they are same meaning. I add, in degree they are close meaning to "perhaps"~ or you can say 應該、大概~~to convey not certain

"ke neng" or "ye xu ba" mean guess,presume sth. if you are not sure about sth,you can say that. in my opioion,they are same meaning.