if 

conj.  （表示條件）如果；（表示假設）假如，要是 ; 但願

If I were you, I would never do that.

If only, I were rich!

if only I'd listen to you.

n. 條件；設想[C]

There are too many ifs in his offer.

adv.  否則 ; 恰恰相反

Are you ready? If not, I'm leaving. 

She is not thin, if anything, she is plump.