Forms: I studied English.
We use the simple past for many kinds of past events: short, quickly finished actions and happenings, longer stituations, and repeated events.
I spent all my childhood in China.
The simple past is common in stories and descriptions of past events.
One day the Princess decided that she didn't like staying at home all day, so she told her father that she wanted to get a job …
The simple past is often used with words referring to finished times.
I saw Jane yesterday morning.
In general, the simple past tense is the 'normal' one for talking about the past; we use it if we do not have a special reason for using one of the other tenses.