单项选择题
One suggested method of containing the fires was presented by Cary Colaizzi of the engineering firm Goodson, which has developed a heat-resistant grout (a thin mortar used to fill cracks and crevices), which is designed to be pumped into the coal fire to cut off the oxygen supply.
单项选择题 With computers doubling in speed and power every couple of years, and with genetic engineering’sdazzlingfeats growing more and more routine, the battered American faith in technological progress has been growing stronger and giddier of late.
