Because of the great weight pressing down on them, these layers tend to fold downward at weak spots, and this finally causes an actual break in the crust.
由于巨大的重量向下压岩层，使它趋于在它的薄弱处向下折叠，这最终导致地壳的实质断裂。
2
They often fold over or bunch up, turning them into booby traps for anyone shuffling down the hall.
它们经常折叠或堆成一堆，成了任何拖着脚走过大厅的人的陷阱。
3
Don't folddown the corners of the page, it damages the book.