background material短语⁹⁶⁶⁷⁷⁺⁶ 基本例句 背景材料 On the outermost layer, we have some static background stuff, like stars.在最外层,我们使用一些静态的背景材料,例如象星星。 This part concisely summarizes the necessarybackground materialand may be viewed as an appendix.这部分简要概括了必要的背景材料,它可以看作是附录。