Use when, before or after, the past perfect and the past simple to join the sentences, as in the example. 1 The scientist made an announcement. He completed his research.

2 After she had studied for 4 years, she got a degree in engineering./She got a degree in engineering after she had studied for four years.
3 After he had worked as a sales assistant, he got a new job as a car salesman./He got a new job as a car salesman after he had worked as a sales assistant.
4 Anne and David had been engaged for 5 months before they got married./When Anne and David got married, they had been engaged for 5 months.
5 Mr. Harris had been sick for many weeks before he went to hospital./When Mr. Harris went to hospital, he had been sick for many weeks.