Here are the verbs filled in the present perfect or past perfect tense:

5. We went to the box office at lunch-time, but they **had already sold** all the tickets.
6. It isn’t raining now. It **has stopped** at last.
7. It’ll soon get warm here. I **have turned** the heating on.
8. It was twenty to six. Most of the shops **had just closed**.
9. Karen didn’t want to come to the cinema with us because she **had already seen** the film.
10. There’s no more cheese. We **have eaten** it all, I’m afraid.
11. I’m very pleased to see you again after such a long time. We **have seen** each other for five years.
12. I spoke to Melanie at lunchtime. Someone **had told** her the news earlier.
13. By 1960 most of Britain’s old colonies **had become** independent.
14. Don’t you want to see this program? It **has started**.
15. At first I thought I **had done** the right thing, but I soon realized that I **had made** a serious mistake.