Complex Subject. English. Help

Я нашла в интернете тему Complex Subject,но я не могу разобраться, как их трансформировать
Transform the sentences using the Complex Subject:
1 . They expected him to return in a fortnight.S.Everybody supposed him to be a foreigner. 3. It is believed that she knows several foreign languages. 4. It is reported that the delegation arrived in Paris on the 10th of September. 5. It turned out that the text was very difficult. 6. It is supposed that the book will'be published next year.7. It seems that he knows a lot. 8. It is said that Kate is preparing for her entrance examinations. 9. It is considered that the picture is a real masterpiece. ->10. It is said that she has been teaching Maths for twenty years.