-(y)AN  / -(y)AcAK : who / which / those  / (that *)

 When we address to group of people or when you refer to certain group of people , in stead of asking each person Do you ..?, Are you …? etc. we can use

-(y)An var mı?                                             is there someone (among you)  who …ed ; …s ;  is …ing

-(y)AcAk olan var mı?                              is there someone (among you) who will …

-(y)An / -(y)AcAk kimse yok.                 there is nobody who…

-(s)I ol-an                                                      Someone (among you) who/which has ; had

-(s)I ol-an var mı?                                       is there someone who/which has …

-(s)I olan kimse yok                                   there is nobody who has

-(s)I olma-yan var mı?                               is there someone who/which doesn’t have …

-(s)I ol-an  yok mu?                                    isn’t  there anybody who/which has …

-(y)An yok mu?                                           isn't there anyone who …ed / …s / is …ing

-(y)AcAk olan yok mu?                            isn't there anyone who will …

ADJ. NOUN ol-an var mı?                           is there someone (among you)  who IS  ADJECTIVE, NOUN

-(s)I ol-an                                                      the one who/which has 

-(s)I olma-yan                                              the one who/which has not

you should pay attention that biri (or birisi )  means someone in Turkish so you can use constructions above only and only in these cases otherwise ,if you want to say “I want someone who understands me” you should use  biri (or birisi ) e.g Beni anla-yan birini istiyorum

and pay attention you should use n buffer after biri-n-… (or birisi-n-… )

-(s)I ol-an                                                      … who/which has 

-(s)I olma-yan                                              … who/which has not

*that ; when you can replace that with who/which you should always use  -(y)AN  / -(y)AcAK 

**who ; when you can replace who with whom you should always use kim+  …-DIğ / -(y)AcAğ

you can drop the noun

-(y)AN  / -(y)AcAK  : the one(s) the people who/which

but when you drop the noun for -(y)AcAk  singular you have to add olan i.e 

-(y)AcAk olan : the one which / who will