The main concept to introduce when teaching the past continuous is the idea that the past continuous expresses an interrupted action. In other words, the past continuous speaks about what was going on when something important happened. The past continuous can be used by itself to express what happened at a precise moment in the past. However, the most common use is together with the past simple - ... when something happened. You might want to consider teaching the past simple together with the past continuous for intermediate level classes, as the past simple will be review for students.
Introducing the Past Continuous
Start by Speaking about What Was Interrupted
Describe an important past event and then fill in the details as a painter would fill in background details by using the past continuous form. This immediately illustrates the idea that the past continuous is used to set the context of what was happening at that moment in time.
I'd like to tell you about the day I met my wife. I was walking through the park, the birds were singing and it was raining just a little bit when I saw her! She was sitting on the bench and reading a book at that moment. I'll never be the same. etc.
This example is admittedly exaggerated. However, it conveys the point. Continue introducing the past continuous by asking students simple questions in the past simple about events. Follow up these questions with a question asking what was happening when...
When did you leave home this morning - At nine o'clock.
What was your sister doing when you left home?
Where did you meet your girlfriend? - At school.
What were you doing when you met her?
The next step in teaching the past continuous is to include simultaneous actions using 'while'. Explain that 'while' is used when two actions happen at the same time in the past. It's a good idea to point out the difference between while and during, as well to help avoid future confusion.
Practicing the Past Continuous
Explaining the Past Continuous on the Board
Use a past continuous timeline to illustrate interrupted action. Contrasting this timeline with past continuous for something happening at a specific point in the past may help illustrate the difference between the two uses. Make sure that students understand the use of time clauses with 'when' and 'while' to help them use the past continuous in context.
Comprehension activities such as using photos in magazines will help with the past continuous. In this case, make it clear to students that they are to describe the event in the past. You can model this by using a photo in a magazine to describe such an event. Dialogues beginning with "What were you doing?" will help students practice. A creative writing exercise on the past continuous will also help students build their ability to integrate the past continuous into more advanced structures.
Challenges with the Past Continuous
The single greatest challenge to the past continuous is deciding which action is the main event. In other words, which event interrupted the action in progress in the past moment in time. Other challenges can include the use of the past continuous to express an activity that happened over a period of time. It's crucial for students to understand that the past continuous describes a particular moment in time, and not a completed event. Here are examples of this type of issue:
I was studying my homework yesterday.
She was cooking dinner last night.
In other words, the past continuous needs the context of another event when stopped the action in progress at the time.