unless , if , Maybe....

它們的分別如下：
unless 是 連接詞 : 1.如果不, 除非
I won't apologize unless she apologizes first.
除非她先道歉, 否則我不道歉
===========================if 是 連接詞 : 1.(表示條件)如果
He will come if you invite him.
如果你請他, 他會來的。2.(表示假設)假如, 要是
If I were you, I would never do that.
如果我是你, 我決不做那件事。3.(表示讓步)即使
We'll go even if it rains.
即使下雨我們也要去。4.是否
I wonder if she is ill.
不知她是否病了。5.(表示因果關係)每一次...的時候(總是會)
If I feel any doubt, I inquire.
我一感到有疑問就隨時詢問。
================================Maybe = 副詞： 1.大概, 或許, 可能
Maybe you'll have better luck next time.
也許下次你的運氣會好一點。