To get the $900 billion number, the group studied four coal districts in India and identified eight different cost elements.

为了得到9000亿美元的数字，该组织研究了印度的四个产煤区，并确定了八个不同的成本要素。

Both doors and lattices were open; and yet, as is usually the case in a coal district, a fine, red fire illumined the chimney: the comfort which the eye derives from it renders the extra heat endurable.

门窗都敞开着；但是，正如在产煤地区的通常情况，一炉烧得红红的好火把壁炉照得亮亮的：由这一眼望去所得的舒适之感也使那过多的热气成为能够忍受的了。