Your E-Prime example reads a lot better and clearer than the book's[1]. :-) Thank you anew!
------------------------
[1] The book from which I have taken all the excerpts so far,
English for Business - A functional approach, 2nd Edition, ISBN # 0-8264-5857-2. Printed in UK.
Don't let a spammer's advertisement ruin it. I just don't even read their ads; they usually contain a lot of "is of predication" together with a lot of "is of identity". That alone turns me off. We can simply ignore them.
Shall we proceed with the challenge?
"Most of the tractors on offer at the present time
are over-priced for this market and the spare parts
are too expensive."