We use this tense:

• to talk about events or actions that happened in the past which have no connection to the present:
  Ex. She wrote the letter on Wednesday. (Today is Monday)
  
• to talk about a finished action in someone’s life:
  Ex. Mary’s uncle went to Spain twice.  (Mary’s uncle is dead)
• to tell a story or a series of single past completed events or actions:
  Ex. I went to the library, then I looked for the books I needed to write the essay, I read them, and, finally, I started writing it.
• to talk about habits in the past:
  Ex. When I was a teenager I visited my uncle twice a week.
• to talk about past facts or generalisations:
  Ex. People paid much more to make cell phone calls in the past.
• with a finished time word (yesterday, last week, last month, in 2002, etc.) but no time reference is necessary if it is already known:
• Ex. It was very cold yesterday.
• to talk about long-term situations in the past which are no longer true:
  Ex. She worked at the hospital for over fifteen years.

C= CONSONANT      V = VOWEL