0 used in questions etc when asking someone to point out, state etc one or more persons, things etc from a particular known group -- welche
1 (used to refer to a thing or things mentioned previously to distinguish it or them from others; able to be replaced by that except after a preposition; able to be omitted except after a preposition or when the subject of a clause) (the) one(s) that -- welche
2 used, after a comma, to introduce a further comment on something -- welche