The key answer of exercise 4
The key to exercise solutions in chapter Self-check 7 for the textbook Focus 4 - Workbook with authors Daniel Brayshaw and Beata Trapnell from Pearson Education
Question
Rewrite the sentences using passive forms.
Answer
- was thought that
- is said to have had
- were estimated to be
- is claimed to cause
- is known to have revolutionised