训练二 完成表格型
阅读下面短文，完成表格。
(一)土壤知识(2015，葫芦岛)
You probably don't think about soil often，but the following report may help you learn about science of soil.
What is soil made of?
Soil is made of sediments (沉积物) and humus (腐殖质)．Sediment is small pieces of rock broken down over time by rain，ice，and wind.Sediment is often found in water.Humus comes from decayed (腐烂的) plants and animals.It helps give plants a lot of the food they need to grow.
How does soil form?
●Over centuries，rock breaks down into very small pieces.
●The rock pieces mix with humus.
●The humus gets thicker and thicker over time.Soil is formed (形成)!
