首先是“结论-解释型”文章。这类文章在开始有一个判断句,一般是文章的结论,也是文章的主题。这个判断句的谓语部分通常包含系动词(is, remain,prove, turn out, appear等)或情态动词(can, may, should,must等),而且含有表示态度的词汇(如形容词等)。例如:
Because of its accuracy in outlining the Earth's subsurface, theseismic-reflection method remains the most important tool in the search forpetroleum reserves. In field practice, a subsurface is mapped by arranging aseries of wave-train sources, such as small dynamite explosions, in a gridpattern…