Past simple or Past Simple Continuous

Question

I have a problem with correct understanding difference while I should use past simple continuous or past simple.

The simple past can also be used to describe a habit which stopped in the past. It can have the same meaning as "used to." To make it clear that we are talking about a habit, we often add expressions such as: always, often, usually, never, when I was a child, when I was younger, etc.

Examples:

I studied French when I was a child. He played the violin. He didn't play the piano. Did you play a musical instrument when you were a kid? She worked at the movie theater after school. They never went to school, they always skipped class.

So let’s take a look at first example:

I studied French when I was a child.

When I say:

I was studying French when I was a child.

Is grammatical?

Answer 1

It's grammatical, but it's unnecessary. As with many languages the continuous form of the verb is used to express simultaneous action -- something happening while something else is also happening.

As a child I was playing soccer when I was tackled by a much larger boy who nearly broke my leg. Ever since then I've avoided sports.

If you just want to express an event that happened in the past, unrelated to other events, use the simple past:

I always ate all my vegetables as a child. I still love them today.