Quote Originally Posted by Antonio1986 View Post
- Why you didn't come early?
- I was studying.
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- Почему ты не приехал рано?
- Читал.
Actually, your translation is incorrect. "Читать" doesn't mean "to study".

- Почему ты не приехал рано?
- Читал. = I was reading.

The correct translation:
- Почему ты не приехал рано?
- Занимался. (= Я занимался)
it means a person was doing their homework or something like that.

Рано = early
Раньше = earlier
Perhaps, you had to use "раньше" instead of "рано". It depends on what you meant, but your variant is uncommon anyway. If the asking person implies something like "I have been waiting for you for such a long time!", you should use "раньше".