GRE Text Completion: JiJing 1373-GRE填空机经1373题 - 7HETB4AGBYGNC6ANA

Substantial atmospheres around planetary bodies act as (i)____________ incoming objects. Smaller objects, particularly those that are lower in density and more fragile, (ii)____________ in the upper reaches of the atmosphere, whereas more intact, larger bodies may survive to impact the surface. Thus, relative to large craters, small craters are much less (iii)____________ on bodies with dense atmospheres, such as Earth, Venus, and Titan, than they are on Mercury and Moon. A. effective obscurers of B. vaporize C. unusual D. significant filters to E. proliferate F. persistent G. impenetrable barriers against H. agglomerate I. common