Now, complete these rules! 1. We use + past participle to say that an event or situation was possible in the past.

2. We use + past participle to say we are sure something didn't happen or was impossible in the past.

3. We use + past participle to say we are sure that something happened or was true in the past.

In which type of essay would you expect to find the following passage? during the civil war, the economies of the northern and southern states differed: the north was industrial, while the south was agricultural. while sometimes these interests allowed for mutual economic goals, they also contributed in part to the conflict that fueled the onset of the civil war.