Why we use past perfect continuous instead of past continuous in these 2 examples?

Question

As you see in these below examples, they used past perfect continuous, but I thought it should be past continuous because they are both in shorter periods and didn't emphasize duration. And even in the second example, I saw it use a background and focus on it. Can you help me with these examples?

1-I was disappointed when I had to cancel my holiday. I (was looking forward to it/ had been looking forward to it).
2-When I got home, Mark was sitting in front of the TV. He had just turned it off. He (was watching a film/had been watching a film).

Answer 1

Either is acceptable, at least in American English. The past tense refers to the past in general, and the other makes reference to another event or activity that establishes a specific time when this event or activity happened.

I was looking forward to it.

He was watching a film.

These refer to the past in general without reference to any other events or activities.

I had been looking forward to it.

He had been watching a film.

This makes reference to another event or activity that designates a specific point in time. In the first example, it's the point when you cancelled your holiday. In the second example, it's the point when you got home.

Answer 2

In both examples there is a narrative time. This is the time of the events being told in the story, and the narrative time is in the past. So we use "past tense" to describe the events that happen at that narrative time:

I was disappointed... (when I had to cancel...)

Mark was sitting ... (when I got home)

To talk about events that occurred prior to the narrative time (but with effects at the narrative time) you may use the past perfect.

The event "be looking forward" was before the narrative time ("when I had to cancel my holiday") so the past perfect may be used.

The event "be watching a film" finished prior to the narrative time ("When I got home") and so the past perfect may be used.