形容词
中文翻译：坚硬的
同义词：
['hard', 'tough', 'intractable']
例句：
-
1. The rocks are Ni-hard, making it difficult to drill through them.
这些岩石坚硬，很难钻透。
-
2. The soil is very Ni-hard, requiring a lot of water and fertilizer to grow crops.
土壤非常坚硬，需要大量的水和肥料才能种植作物。
-
3. The metal is Ni-hard, which makes it suitable for use in cutting tools.
这种金属很坚硬，适合用作切割工具。