2014
高考英语完形填空基础训练题（113）及答案 passage thirty-five (exploration on the origin of continents) the origin of continental nuclei has long been a puzzle. theories advanced so far have generally failed to explain the first step in continent growth, or have been subject to serious objections. it is the purpose of this article to examine the possible role of the impact of large meteorites or asteroids in the production of continental nuclei.
