扫描二维码，直接登录
题库 / Prep2007E1-SC-23
While they remove carbon dioxide from the air, conserve soil and water, and house thousands of species, forests also supply potentially valuable pharmaceuticals, and, as sources of building material and firewood, that provide employment for millions worldwide.
pharmaceuticals, and, as sources of building material and firewood, that provide
pharmaceuticals, and sources of building material and firewood, are providers of
pharmaceuticals and, as sources of building material and firewood that are providing
pharmaceuticals and sources of building material and firewood, for providing
pharmaceuticals and, as sources of building material and firewood, provide
还没有题目讲解（毕出老师会陆续发布对官方考题的解读，请保持关注）。
forests supply pharmaceuticals and provide employment ...两个动词supply和provide需要平行
choice b, supply 1)pharmacy and 2) source of building material and firewood意思变成了两个宾语并列。导致了supply和are providers之间没有任何连词
登录 或 注册 后可以参加讨论