1,2 and 4 are mostly differences in aspect. finnas and vara are infinitive, the basic form of the verb, while finns and är have been changed according to person. So it depends on who you're talking about. Han finns, de finns = he exists / present tense with singular AND plural objects of "att finnas" att finnas = to exist att vara = to be är, jag är, de är, dem är, hon är = he is, she is, you are, i am, they are / present tense with singular AND plural objects of "att vara" att gå = to walk jag går = i walk / present tense OR I am walking / progressive tense... I think this depends on context but I'm not that good at Swedish verbs and how progressive works in Swedish, theoretically. The words in number 3 are prepositions, except for "som" which is the Swedish equivallent to English "that".