GRE Reading Comprehension: JiJing 352-GRE阅读机经352篇 - 5OVX74P55G8VK0OLJ

The primary purpose of the passage is to A. explore an analogy between aspects of the geology of Mars and the geology of Earth B. describe how a certain feature of Mars's surface formed C. point out the effect that new data has had on a scientific investigation D. summarize potential explanations of a large-scale geological feature E. present the rationale for a scientist's theory and expose some of its weakness