Balkstone
含杂质的层状灰岩
🗣️ 情景例句
It's common practice.
这是惯例。
Don't cast out the foul water till you bring in the clean.
清水未来，莫泼赃水。
The woman immediately behind the two cars happened to be a learner.
紧跟其后的一辆车上的司机碰巧是个初学者，