中に vs 中 - When to use に. テスト中に私の携帯が鳴ってしまった


> テスト中に私の携帯が鳴ってしまった。

Means: My phone accidentally rang during the test.

Can someone explain why the particle に is required after the 中?

Why does: テスト中私の携帯が鳴ってしまった。

Not work here?




Here に is an article used with time. In spoken Japanese, it can be considered
obvious and dropped completely. In spoken Japanese, it would be replaced with
a pause, or, if writing out spoken Japanese, with a comma to indicate the
pause.テスト中、私の携帯が鳴ってしまった。

