Ответ:

4. Put the verbs in brackets in the Past Simple or the

Past Perfect tense form.

1. After ten people had eaten that chicken they all fell ill. 2. We didn't stop until  we had finished our home assignment. 3. Two men delivered a sofa which I had already paid for. 4. 1 gave the book to my friend after I had read it. 5. Jane signed the  letter which she had typed herself on her word processor. 6. 1 pulled out into the  road after I had looked both ways. 7. We handed the forms in after we had completed them. 8. When the pupils had done the experiment, they wrote a report on it. 9.  We had put out the fire already when at last the firefighters arrived. 10. They  went out after their mother had come home from work.​

Объяснение:

Надо разобраться, какое действие было сначала, а какое за ним последовало. То, которое было первым, обозначается Past Perfect, которое имело место за ним - Past Simple.