词汇讲解:
1. protection n.保护
例句:The best protection against global warming is global prosperity.
防止全球变暖的最好防护是全球繁荣。
2. gather vt.收集; 聚集
例句:All the members of the family gather to enjoy a reunion dinner.
全家人聚在一起吃团圆饭。
3. optimum adj.最适宜的
例句:The optimum density is difficult to specify in terms of trees per acre.
很难定论究竟每英亩多少株树为最适密度。
4. substance n.物质,材料; 实质
例句:These attacks place form above substance.
这些抨击都是形式重于内容。
5. install vt.安装; 安顿,安置; 任命
例句:He's going to install an air-conditioner in the house.
他要在这屋子里装空调机。