protectionistn.保护贸易论者adj.保护贸易论的protectionn.保护；防卫protection programming保护规划protection and renewal保护与更新protection coefficient防护系数protection of resource资源保护protection on the move行军警戒protection malfunction保护误动protectionist reaction保护主义的应对措施protection for animals动物保护protection ring system保护环系统protection engineering防护工程

1. The city covers an area of 15 square kilometers.
   该城市的面积为十五平方公里。
2. We can compute the circular area with radius.
   我们能用半径计算出圆的面积。