I know the first usage of "koto ga aru" which is used with -ta verbs to say " I have done/experienced something before ...."
but I am very confused about the second usage which means "there are times when something occurs/or/ sometimes occurs.
Now, if the structure "present plain verb + koto ga aru" means "sometimes occurs" couldn't the word "tokidoki" be used instead? or are they not interchangeable?
So if I wanted to say " I sometimes study at home." , couldn't I use tokidoki instead of the "koto ga aru" structure?
ex:
A. watashi wa tokidoki ie de benkyou suru. ( I sometimes study at home)
B. watashi wa ie de benkyou suru koto ga aru. (I sometimes study at home./ There are times when I study at home.)
Can someone please clarify my confusion and perhaps give me random sentence examples in romaji along with the English translation?
I would really appreciate any guidance you all can give me! Thank you very mcuh!