Please revise my book review?

Your review is contradictory. You write that the story "is absolutely captivating", and then you conclude by saying that it is "extremely boring". How can it be both? You only read half of the book, you reveal. Agatha Christie is a famous and highly regarded mystery writer, and "Murder on the Orient Express" is one of her most renowned works -- it has been made into a movie more than once. Also, you write that "Agatha needs to work on grabbing the reader's attention..." Agatha Christie is actually dead. Maybe you could write a better review if you would have finished the book! In the event that your report is not due imminently, I'd advise you to read the book, then rewrite the review. If I were your teacher, I couldn't, in good conscience, give you a ping grade based upon your review -- particularly since you haven't read the book!