Past Progressive
Past progressive describes something that happened in the past, but has now stopped. It is achieved by combining a 'to be' verb (is/was/were) with the -ing form of the verb. So, what if Greg fell in hole while he was running?
Greg was running through the campground, but then he tripped and fell in a hole.
Past Perfect
So in past progressive, Greg stopped running because he tripped; but what if he decided to stop running when he saw the hole? Past perfect describes an action that was completed before something else in the past happened. It is accomplished with 'had' plus the past participle of the verb:
Greg had run through the campground, but stopped when he saw the big hole.
Past Perfect Progressive
So now, what if Greg saw the hole, but he didn't stop running? Past perfect progressive describes an event that happened and continued through another event. It is achieved by combining 'had been' with the -ing form of the verb:
Greg had been running through the campground when he saw the big hole.
Past Habitual
What if you want to describe not one particular event in the past but something that happened regularly? That is called the past habitual:
Greg used to run through the campground every day.
Less Common Past Tense Forms
So, we've covered the most common past tense forms that you are likely to use on a daily basis, but there are a few more that may come up occasionally.
Time-Specific Past Habitual
For instance, let's look at time-specific past habitual. This one is similar to past habitual (if you didn't gather from the name), but specifies a certain time when it stopped. This is accomplished with the word 'would' and the simple present tense. It also typically follows the specific reference to the time when it stopped:
Before he moved away, Greg would run through the campground every day.
Past Intensive
Next we have past intensive. This tense confirms something happened in the past and uses 'did' plus the present tense form of the verb:
Greg did run through the campground; I saw him.
Future in the Past
Finally, we have future in the past. As the name implies, this one gets a little confusing, but just describes something that was going to happen but now isn't. It uses 'was' or 'were' plus the -ing verb:
Greg was going to run through the campground, but decided not to.