plain + とき + plain or polite?


If I use the plain past tense of a verb before とき, do I have to use the plain
past tense in the sentence that comes after it, or is it okay to use the
polite past tense? For example, I'm trying to say, "When I went to Japan, I
did not ride the shinkansen."

[code]

    日本に行ったとき、新幹線に乗らなかった。
    
[/code]

vs.

[code]

    日本に行ったとき、新幹線に乗りませんでした。
    
[/code]

Are they both correct? If so, which one is preferred? There's an example on
[this page](http://www.learn-japanese-adventure.com/toki-in-japanese.html)
that uses the polite past in the sentence that comes after とき.

[code]

    日本へ行ったとき、カメラを買いました。
    
[/code]




They're both correct, it just depends on the context in which the sentence
appears.

For example, if it were in a speech you would most likely say:

日本に行った時、新幹線に乗りませんでした。

However, perhaps in casual conversation with a friend you'd be more inclined
to say:

日本に行った時、新幹線に乗らなかった。

Hope that helps!




They're both correct, it just depends on the context in which the sentence
appears.

For example, if it were in a speech you would most likely say:

日本に行った時、新幹線に乗りませんでした。

However, perhaps in casual conversation with a friend you'd be more inclined
to say:

日本に行った時、新幹線に乗らなかった。

Hope that helps!

