It studies these populations in the past, present and future using quantitative data and mathematical models as tools of analysis.

它使用定量数据和数学模型作为分析工具，研究这些人口在过去、现在和未来的情况。

youdao

It studies these populations, in the past, present and future, using quantitative data and mathematical models as tools of analysis.

它使用定量数据和数学模型作为分析工具，研究这些物体在过去、现在和未来的数量。

youdao

I want to tell you about the past, present and future of the human population. So let's start with a few problems.

我想告诉你们有关人口数量的过去、现在和未来。那么让我们从一些问题入手。

youdao

It goes back to the time of Buddha, who believed that the mind should always be fully in the present -- not looking back at the past or anticipating the future.

CNN: Mindfulness training busts stress

Our nation is one of compassion and understanding, and we have to understand that this country was built by immigrants - our past, our present and future.

NPR: May Day Immigration Marches Lose Some Steam

Nonetheless, thousands gathered all along the wall to celebrate and talk not only about the past and the future, but also about the joy-filled present.

CNN: How I brought down the Berlin Wall