Past simple vs. past continuous

Introduction

Past simple

We use the past simple to describe:

finished actions in the past:
- "I studied for an exam."
finished actions over periods of time in the past:
- "I studied for four years."
habits in the past:
- "I studied every night when I was at school."
past facts:
- "I studied history at university."

Past continuous

We use the past continuous:

to emphasise the continuous nature of a finished action in the past:
- "I was studying for an exam all night."
to describe a continuous action that was in progress at a particular time:
- "At 11am, I was visiting my grandmother."

We do not use the past continuous for habits in the past: not "~~I was taking the bus to school.~~"

Past continuous vs. past simple

We can use the past simple and the past continuous in the same sentence structure with different meanings:

The past simple describes when the action started:
- "At 7am, I went to work."
  This means that the journey to work began at 7am.
The past continuous describes an action that was already in progress:
- "At 7am, I was going to work."
  This means that the journey to work was already in progress at 7am; it began before 7am.

Using "when" and "while" to describe actions that happen at the same time

"when" and past simple

We use "when" with the past simple to describe two actions where one action is the result of another action, or happens immediately after:

"I went downstairs when I heard the doorbell."
or
"When I heard the doorbell, I went downstairs."

The action of going downstairs is the result of hearing the doorbell.
"What did you do when the telephone rang?"
This question asks about your action as a result of hearing the telephone ring.

"I left the house."
The answer means that immediately after the telephone rang, you left the house (suggesting that you did not answer the telephone).

"when" with past continuous and past simple

We use "when" with the past continuous and past simple:

to describe an action that was in progress (using past continuous) when another action happened (using past simple):
- "I was studying history at university when I learnt to play the saxophone."
to describe a continuous action that was already in progress (using past continuous) and was interrupted by a shorter action (using past simple):
- "I was going downstairs when I heard the doorbell."
  or
  "When I heard the doorbell, I was going downstairs."
  The action of going downstairs was already in progress and was interrupted when the doorbell rang.
- "What were you doing when the telephone rang?"
  This question asks about the action that was interrupted when the telephone rang.
  "I was leaving the house."
  The answer means that before the telephone rang, you were already in the process of leaving the house (suggesting that it is possible that you did answer the telephone).

"while"

We use "while" with the past continuous to describe a continuous action that was in progress at the same time as another action, using either the past simple or past continuous:

"She read the newspaper while I was doing the gardening."
or "While I was doing the gardening, she read the newspaper."
"She was reading the newspaper while I was doing the gardening."
or "While I was doing the gardening, she was reading the newspaper."
"What were you doing while the telephone rang?" This question asks about your action at the same time as the telephone rang (suggesting that you were doing something else instead of answering the telephone).