The surface of Venus calcite, a mineral that absorbs the gas sulfur dioxide. Sulfur dioxide is often produced by volcanic activity and is plentiful in Venus’atmosphere, so there must be a source, perhaps volcanic, producing sulfurdioxide on Venus.
1. Whichof the following is an assumption on which the argument depends?
A. In the recent past, the level of sulfur dioxide in Venus’ atmosphere was notmuch
higher than it is now.
B. If there is volcanic activity on the surface of Venus, it is not adequate tomaintain the
observed amount of sulfur dioxide in the atmosphere.
C. The sulfur dioxide in Venus’ atmosphere forms clouds that prevent direct observation of the surface.
D.Sulfur dioxide produced by volcanic activity on the Earth’s surface is also absorbed by minerals other than calcite.
E.The calcite on the surface of Venus is in sufficient supply to continue to absorb sulfur
for millions of years to come.
该题是一道假设题。文章说，金星大气中有很多二氧化硫(sulfur dioxide ), 二氧化硫经常由火山活动产生，由C(calcite )吸收。文章由此得出结论：金星表面应该有来源，很可能是火山，正在产生二氧化硫。