Undercourse
底层, 垫层, 在花砖或瓷砖之下的底层
🗣️ 情景例句
This has been a hard course for me.
这门课对于我来说很难。
Better wear out than rust out.
与其闲散不如忙碌。
I don't know how to express my gratitude.
我不知道怎样来表达我的感激之情。