1. There are much books in the library.
Answer : There are many books in the library.
2. A group of students are discussing the homeworks.
Answer : A group of students is discussing the homeworks.
3. The president of Iran or the president of Turkey are attending the meeting.
Answer : Either the president of Iran or the president of Turkey is attending the meeting.
4. Neither they nor my sons never does the school task.
Answer : Neither they nor my sons never do the school task.
5. Not only my mother, but also my father have been in London.
Answer : Not only my mother, but also my father has been in London.