The solution for exercise 5 in chapter 7.5 - Grammar of Focus 4 - Student's Book by Kay Sue, Jones Vaughan, Brayshaw Daniel and Beata Trapnell
Question
Rewrite each sentence in two ways. Begin with the words in brackets.
Answer
It is known that most mathematical symbols were invented in the 1500s. / Most mathematical symbols are known to have been invented in the 1500s.
The seventeenth century is considered to have been a high point in the history of Mathematics. /It is considered that the seventeenth century was a high point in the history of Mathematics.
3 It was thought that calculators could harm students’ Maths skills. /Calculators were thought to be able to harm students’ Maths skills.
There are estimated to be over 10,000 new Maths graduates every year in the UK. /It is estimated that there are over 10,000 new Maths graduates every year in the UK.