MENGGUNAKAN WHICH

(a)   Tom : May I borrow a pen from you?        Ann :   Sure. I have two pens. This pen has black ink. That pen has red ink                    Which (pen/one) do you want? Tom : That one. Thanks (b)  Which pen do you want? (c)  Which one do you want? (d)  Which       do you want?	In (a): Ann uses which (not what) because she wants Tom to choose Which is used when the speaker wants someone to make a choice, when the speaker is offering alternatives: this one or that one; these or those
(e)   Sue : I like these earrings, and I like those earrings        Bob : Which (earring/ones) are you going to buy?        Sue : I think I’ll get these (f)   Which earring    are you going to buy? (g)   Which ones         are you going to buy? (h)   Which                  are you going to buy?	Which can be used with either singular or plural nouns (f), (g), and (h) have the same meaning