Напишите пять предложений в past perfect continious tense

I had been writing a letter for 2 hours when he came.
I had been reading this book since 3 o'clock when he came.
I had been waiting there for more than two hours when you finally arrived.
I had waited there for more than two hours before you finally arrived.
By the time I came home my children had already gone to bed.

At 5 o'clock she understood that she had been working for 3 hours already.
When I came they had been discussing their plan for two hours already.
I had been sleeping for an hour when the telephone rang.
We had been waiting for half an hour before the train arrived.
I felt very tired last night because I had been working hard since morning.