(1) Sometime 有未来的“不确定的时间”之意；
(2) Sometimes 的意思是“偶尔”,“时不时”；
(3) Some time 的意思是“一段（有限的）时间”.
例:
(A) Why don't you come up sometime and see me?
(B) I am so muddled that sometimes I don't understand a single word of what I am saying.
(C) You must give some time to your fellow men.Even if it's a little thing,do something for
others -- something for which you get no pay but only the privilege of doing it.