 Let's now have a quick review of the past tenses. Here we have four very similar example sentences, each using a different past tense. This should allow us to be able to look at the differences in usage between these tenses. First example, when I arrived, John cooked. When I arrived, John was cooking. When I arrived, John had cooked. When I arrived, John had been cooking. In the first example, when I arrived, John cooked. If we look at John cooked, this is the past simple. The structure is quite simply the subject plus verb in the past tense. The past tense verb is usually formed just by adding ed to the end of the base form. However, again, there are many irregular verbs such as go would change to went, be, to was or were, no to knew. Again, there are no rules for this and they just have to be learnt individually. The past tense here, as we can see, is used for completed past actions. I arrived in the past and John cooked in the past. They give us the order in which past events happen. I arrived first and then John cooked. I woke up and then I got up. I had a shower, I had breakfast and went to work. So the past simple is very useful for ordering actions. The second example sentence, when I arrived, John was cooking. John was cooking is in the past continuous tense. Here, the structure is subject, John, the verb to be in the past tense, which is was or were, plus the verb with an ing at the end. The past continuous tense is used to describe an action that was in progress at a specific past time. Here in the example sentence, the cooking was in progress at the time I arrived. This differs from the first example sentence where I arrived first and then John cooked. In this example, the cooking had already started and was still in progress at the time I arrived.