变故: an unforeseen event, accident, misfortune...
备课: (of a teacher) to prepare lessons...
西部: western part...
依赖: to depend on, to be dependent on...
谦虚: modest, self-effacing, to make modest remarks...
示范: to demonstrate, to show how to do sth, demonstration, a model example...
影像: image...
激化: to intensify...
帐子: mosquito net...
信封: envelope...
