Generic nouns and nominalization with 事, 物, ところ, and の

事(こと) and 物(もの) both mean "thing". 事 is generally used for intangible things like actions or states, and 物 is generally used for tangible things like objects. Grammatically, they are nouns, so just like any other noun they can be modified by verbs and adjectives.

あ、いいこと考えた
Ah, I just thought about something good

美味しいものが食べたい
I want to eat something tasty

所(ところ) is a word that means "place". It is used in similar patterns, including ones about intangible places like moments in time or progress, and aspects of an entity. It is often contracted to とこ.

ちょうどいいところに来ました。
You came just at the right moment. (moment = “place” in time)

やれるとこまでやってみよう。
Let’s keep going as far as we can (lit. let’s do it until the moment we cannot do it)

こういうところが彼女のいいところだ。
This aspect of her is what is good (about her)

All three of these generic nouns can turn entire phrases into nouns. This lets Japanese use phrases like things without using embedded clauses. This is basically a special simplified case of the relative clauses we learned about in Lesson 14.

These generic nouns are the base of common phrases and expressions like the following:

無理をしなければ、死ぬことはないだろう。
As long as you don’t overdo it, there’s no way you will die. 

死ぬことはない is literally somehing like 'there is no “will die” event/moment'.

Another one is <verb>たことがある which literally means something like "the action of having done <verb> exists" and it means "to have done <verb> before":

それはどこかで聞いたことがある。
I have heard of that before somewhere.

こと in particular is often used to nominalize verbs. We do a similar thing in English with the ‘ing’ construction: “To play soccer” is an action, but “the act of playing soccer” is a(n abstract) thing.

In Japanese we can also use の to achieve a similar result. There are some instances where こと and の cannot replace each other, but for the most part their usage is very similar when nominalizing actions.

私は歌を歌うのが好き
I like singing songs

の can also be used as a generic noun to replace a more specific word when what we are talking about can be inferred from context. This works with both adjectives and verbs.

赤いのはいいよ
The red one is okay.