Saying something was happening when something happened


I want to know what is the form for "when" in a phrase like "I was reading a
book, when someone knocked on my door." I'm aware of the usage of "toki" in
phrases like "When I was a teacher..." and "When I talk to someone, they run
away...," but I'm not sure if I can use "toki" for "when" in the phrase I want
to write ( I was reading a book, when someone knocked on my door and I had to
stop reading the book ) . For example, I'm not sure if this phrase with "toki"
does that.

"私は本を読んでいたとき、彼が何か話した"

Because it looks like it means "When I was reading a book, he said something"
which isn't quite what I want to reach.

"I was reading a book, when he said something" < - Is what I want to know how
to write

"When I was reading a book, he said something" ! < - There is a difference




This type of "when" in English is called [non-restrictive relative
clauses](https://en.wikipedia.org/wiki/Non-restrictive_clause) (非制限用法). The
basic idea is that the _when_ -clause gives an additional piece of information
like an independent sentence, rather than adverbially modifying and
"narrowing" the preceding noun.

Non-restrictive clauses appear tricky at first to the eyes of Japanese
speakers who learn English. To translate English non-restrictive clauses
without ambiguity, you often have to rephrase the sentence in various ways.
Sometimes it may be even better to split the sentence into two or more
sentences if the original sentence is long.

See examples here:

  * [関係副詞「非制限用法の when」](https://reibunpo.com/kankei-fukushi/kankeifuku-when-hi.shtml)
  * [関係副詞「非制限用法の where」](https://reibunpo.com/kankei-fukushi/kankeifuku-where-hi.shtml)
  * [関係代名詞「主格・非制限用法の which」](https://reibunpo.com/kankei-daimeishi/kankeidai-which-hi-shu.shtml)

As you can see, you can often translate it as if it were two separate
sentences, and connect them with appropriate conjunctions like と/たら/が/ので.

In your case,

> I was reading a book, **when** someone knocked on my door.  
>  私が本を読んでいた **ら** 、誰かがドアをノックした。  
>  私が本を読んでいる **と** 、誰かがドアをノックした。  
>  私は本を読んでいた。そのとき、誰かがドアをノックした。

Similar examples (although these are not relative clauses):

>   * He ran and ran, **until** he was completely tired out.  
>  彼は走り続け、( **そして/ついに/とうとう** )疲れ果ててしまった。
>   * I knocked at the old door, **before**... _(To be continued)_  
>  私はその古いドアをノックした。 **すると** …… （次回に続く）
>

(I definitely remember the last example using _before_ because it was so
impressive, but I don't know if it's actually common in English novels.)




This type of "when" in English is called [non-restrictive relative
clauses](https://en.wikipedia.org/wiki/Non-restrictive_clause) (非制限用法). The
basic idea is that the _when_ -clause gives an additional piece of information
like an independent sentence, rather than adverbially modifying and
"narrowing" the preceding noun.

Non-restrictive clauses appear tricky at first to the eyes of Japanese
speakers who learn English. To translate English non-restrictive clauses
without ambiguity, you often have to rephrase the sentence in various ways.
Sometimes it may be even better to split the sentence into two or more
sentences if the original sentence is long.

See examples here:

  * [関係副詞「非制限用法の when」](https://reibunpo.com/kankei-fukushi/kankeifuku-when-hi.shtml)
  * [関係副詞「非制限用法の where」](https://reibunpo.com/kankei-fukushi/kankeifuku-where-hi.shtml)
  * [関係代名詞「主格・非制限用法の which」](https://reibunpo.com/kankei-daimeishi/kankeidai-which-hi-shu.shtml)

As you can see, you can often translate it as if it were two separate
sentences, and connect them with appropriate conjunctions like と/たら/が/ので.

In your case,

> I was reading a book, **when** someone knocked on my door.  
>  私が本を読んでいた **ら** 、誰かがドアをノックした。  
>  私が本を読んでいる **と** 、誰かがドアをノックした。  
>  私は本を読んでいた。そのとき、誰かがドアをノックした。

Similar examples (although these are not relative clauses):

>   * He ran and ran, **until** he was completely tired out.  
>  彼は走り続け、( **そして/ついに/とうとう** )疲れ果ててしまった。
>   * I knocked at the old door, **before**... _(To be continued)_  
>  私はその古いドアをノックした。 **すると** …… （次回に続く）
>

(I definitely remember the last example using _before_ because it was so
impressive, but I don't know if it's actually common in English novels.)

