To use (simple meaning)

Past Tenses {Past Simple, Perfect, continuous}

Past Simple

6:45 7:00 7:15 Now (7:30)

• 
  6:45 I took a shower
  
• 
  7:00 I ate breakfast
  
• 
  7:15 I left for work
  

Past Perfect

6:45 7:00 7:15 Now (7:30)

• 
  Before I left for work, I had eaten breakfast and I had taken a shower
  

Example:

• 
  A) 1. I completed five courses.
  

2. I received a certificate

Before I received a certificate, I had completed five courses.

• 
  B) 1. The children went to bed at 9:00
  

2. John arrived home at 10:00

When John arrived home, the children had gone to bed.

• 
  C) 1. She was a manager for 10 years.
  

2. She became a director

Before she became a director, she had been a manager for 10 years