英语语法分析

So, naturally, their first calendar was divided up into three seasons, each based on the river's changes: inundation, subsidence and harvest.

因此，他们的第一个日历系统被自然地分为三个季节，每个季节都是根据河流的变化而划分：淹没期、下沉期和丰水期。

Afterwards during the season of subsidence, the water would subside, or recede, revealing a new layer of fertile black silt and allowing for the planting of various crops.

在随后的沉降季节，水会退去，并露出一层新的肥沃的黑色淤泥，可以在这上面种植各种作物。

Land subsidence has been aggravated by overpumping of underground water and the construction of thousands of high-rise buildings.

过度抽取地下水和建造成千上万的高层建筑加剧了地面沉降。