In recent years, oil______ (substitute) for certain natural materials.

admin2009-05-28  29

问题 In recent years, oil______ (substitute) for certain natural materials.

选项

答案has substituted

解析 动词时态。根据时间状语in recent years(通常用于完成时态),此处需用现在完成时。
转载请注明原文地址:https://kaotiyun.com/show/jSvK777K
0

最新回复(0)