Is there a suffix that is the same as -ing in Finn that is used to show present tense action or past tense? No, this is the issue that is hard for Finns in IE-languages :) You still may form similar meaning in past using -ssa/-ssä ending, but that is not exactly same, but still correct.    Example:    I was running, when it started to rain -> Olin juoksemassa, kun alkoi sataa     Now,  Verbix  says that form juoksemassa would be III Infinitive inessive instead of IE usage for imperfect.     Finn doesn't use verb to tell if activity was done already or was it while. I demonstrate with examples:    I was reading the book, when rain started and  I read the book, when rain started.  At first rain started while speaker was reading, but in second rain started after speaker had read the book.     Finn would say these as:  Luin kirja a , kun sade alkoi and  Luin kirja n , kun sade alkoi.  At first one book (kirja) is in partitive and in second as accusative. Partitive indicates that book is not yet read totally, but accusative indicates that book is read till end.    I hope this wasn't too messy..