Вот подробное решение с правильным спряжением глаголов в нужных временах:
At last the librarian gave me the book which I had been waiting for during two months. I was very glad. I went home and began reading it at once.
Don't speak to him: he is very busy, he is doing some very urgent work.
I did not want him to go there: I was afraid that something would happen.
I did not notice that my watch had stopped, and when I arrived at the station, my train had left and I had to ask when the next train was coming.
He had been waiting for fifteen minutes when at last he saw her at the end of the platform.
By the end of the year he had read about two hundred pages.
We were happy when the sun rose, for the night had been very cold.
Where have you put my dictionary? I cannot find it anywhere.
I had not yet fallen asleep when the telephone rang.
What were you doing from six till nine yesterday?
The children were playing here at eleven o'clock, but now they have gone home.
Go to see your old grandfather as soon as you arrive in Novgorod.
You always spend summer at the seaside? - Yes, as a rule. Last summer I went to the mountains, but I did not find the rest there as pleasant as near the sea.
When they returned, they told us a lot of interesting things which they had seen during their journey.
When I left home, it was raining.