Angol! A második mondat miért van Future perfect continuous-ban?

Csak ezzel a mit gondolsz típusú szerkezettel együtt találkoztam vele.

“What do you think the men were doing in the store room?”

“Don’t worry. They will have been unpacking boxes.”

Köszi előre is!

[link]

Future perfect continuous

Use:

Use the future perfect continuous to talk about an event that will be in progress for some time before a specified time in the future.

Janet will be really tired when we get home. She will have been looking after the children all day!

It can be used to make predictions about event that will be in progress before a specified time in the future.

Joe won’t mind that we are late. He won’t have been waiting long.

It can be used to predict what was happening in the past.

“What do you think the men were doing in the store room?”

“Don’t worry. They will have been unpacking boxes.”

Both the fixed future time and the length of time of are often mentioned in future perfect continuous sentences.

By the end of this week, I’ll have been working here for five months.

Fixed future time: the end of this week

Length of time: five months

But this is not always the case.