Refringency
折射系数
🗣️ 情景例句
Hello, how are you doing today?
你好， 今天怎么样？
A friend in court is better than a penny in purse.
曩中有钱，不如朝中有友。
We need some meat.We haven't got any meat at all.
我们需要些肉。我们一点肉也没有了。