A: I have read a book. But I just remember several sentences. I wonder where they are from.
B: Tell me one sentence, maybe, I can help you.
A: OK, one is "His grandfather was a trooper in Monk's army, and one of the parties of dismounted dragons, which formed the forlorn hope at the storming of Dundee in 1651."
B: Oh, let me see. Oh, I know. It is from Walter. Scott's novel: The Heart of Mid-Lothian.
A: Thanks a lot.
exp. An undertaking that seems very unlikely to succeed. （渺茫的希望）
e.g. This plan you have is a forlorn hope and will never work out the way you want.
e.g. Going to their rescue in a rowing-boat is a bit of a forlorn hope.
e.g. I must now bring my forlorn hope into action, in order to carry my point!
e.g. This was a forlorn hope--he was almost sure that Wilson had no friend: there was not enough of him for his wife.