As geologists, we examine layers of sediment on the Earth' s surface to approximate the dates of past geologic time periods.
作为地质学家，我们研究地球表面的沉积层以估算过去地质时期的年代。
2
Vineyards can be sprayed with different pesticides during different growth periods of the grape, and no amount of washing or peeling will eliminate contamination because of the grape \ 's thin skin.