I think everyone has already read about "koto" and "no" before in textbooks and grammar books. In this post, I'll cover "koto" and "no" from my own point of view, and you might come across some points that differ from your own current understanding.
However, there is some ambiguity between "no" and "koto", even when observing how Japanese people use them, so please note that ther might be cases in which you might feel that using either is fine.
First, let me expalin the role of "koto". You've seen that some sentences contain verbal phrases + "koto". The verbal phrase represents an action or state, and "koto" conveys it into a concept that can be used to represent events, incidents, facts, circumstances, and experiences, etc. To state it in grammatical terms, verb + "koto" makes it possible to convert verbs into nouns.
Additionally, "no" performs the same role as "koto". Appending "no" to an action or state converts it to a concept. Also, "no" can represent people, objects, places, times and reasons, too.
This is easier to understand through examples, so let's look at some example sentences. (I'll reuse some of the same sentences from the quiz two posts back.)
- (A-1) Mainichi joggingu wo tsuzukeru koto/no wa muzukashii.
- (A-3) Watashi wa shiranai machi ni iku koto/no ga suki desu.
- (B-3) Uta wo utau koto/ no to, odoru koto/no, docchi ga suki?
- (B-5) Gaikokugo wo benkyou suru koto/no wa jikan ga kakaru.
- (B-4) Watashi no shumi wa e wo kaku koto desu. (correct)
- Watashi no shumi wa e wo kaku no desu. (incorrect)
- Yamada-san ga Amerika ni hikkosu koto/no wo shitteiru?
- Kanojo wa ninshin shite iru koto/no ga wakatta.
- Keitai ga kowarete iru koto/no ni ki ga tsuita.
- watashi wa mae ni kare ni Osaka de atta koto/no wo wasurete ita (or, omoidashita).
- (B-2) Kono mise no namae wo kiita koto ga aru? (correct)
- Kono mise no namae wo kiita no ga aru? (incorrect)
- Tomodachi wa watashi ga hikkosu no wo tetsudatte kureta.
- Watashi wa eki de kare ga kuru no wo matte iru.
- Kagi wo shimeru no wo wasurechatta.
- Daietto wo suru! Amai mono wo taberu no wo yameru.