1. That as much as one-fourth of all timber harvested is not used proved to be false.
解析:
句子的主干是:That 引导名词性从句作主语,谓语动词是proved,to be false 是不定式作表语;在主语从句中,主语是timber,as much as one-fourth of all是主语timber 的前置定语,harvested 是timber 的后置定语,谓语是is not used;此句中that 引导的名词性从句置于句首,表面上看头重脚轻,实际这是一种语言修辞,是一种强调手段