GRAMMAR DETAIL

のを

doing ... as an object

Turns the preceding clause into a noun-like unit and presents it as the direct object of the following verb.

Examples

弟が庭を走るのを窓から見た。

I watched my younger brother run through the yard from the window.

鳥が空を飛ぶのを子どもたちが見上げていた。

The children looked up and watched a bird fly through the sky.

子どもが歌うのを静かに聞いていた。

I quietly listened to the child sing.

Structure: の turns a clause into a noun-like unit, and を marks that unit as an object.
Basic usage: In 子どもが歌うのを静かに聞いていた。, the child's singing is what was listened to.

Subjects inside and outside the clause
- In 弟が走るのを私が見た, the younger brother runs and the speaker watches. Distinguish the subject of the clause before のを from that of the following verb.
Nominalization and object marking
- 歌うのが好きだ expresses liking to sing, while 歌うのを聞いた describes hearing someone sing. Choose the particle after nominalization according to its relationship with the following predicate.