Past Perfect Continuous signal words

Grammar Past Perfect Continuous diagram Past Perfect Continuous form Past Perfect Continuous use Past Perfect Continuous signal words	Exercises Past Perfect Continuous

For

The water had been boiling for half an hour before anybody noticed it.
In 2014 The Browns had been living in London for twenty years.

Since

It was now seven o'clock and he was tired because he had been working since dawn.
I had been working for Nike since 2005.
We had been waiting for Chris since morning when he finally arrived at 4 p.m.
She had been studying since morning and felt very tired.

When

They had been watching TV when the lights went off.
She had been working at that company for three years when it went bankrupt.

How long

How long had you been waiting before she came?
How long had you been waiting to get on the bus?
How long had you been studying English before you moved to London?

Before

I had been sleeping for three hours before the alarm clock went off.
They had been talking for over an hour before Tony arrived.
James had been teaching at the university for more than a year before he left for London.