RARE STRUCTURES in COMMON ENGLISH

I had stayed in a lot of places like Dubai before settling in Kerala.

I had been working for almost 15 years before setting up my own business.

By 6 pm, 6th of April, we will have completed our elections.

Now the questions:

Had you stayed abroad before settling here?

Had you been working for long before setting up your own company?

Will you have completed your elections by April 6th?

(These type of sentences are rarely used while asking questions. They are mostly used in giving formal speeches and writing letters.)

In the first sentence, we are talking about two past actions.

In the second sentence, we are talking about a live action in past plus duration of time.

In the third sentence, we are talking about a future action with a deadline or a time limit.

------------------------------------------------------------------------------