B. The pronoun it either has no referent, or it refers to colors, which is not only illogical but is also an instance of noun-pronoun disagreement in number. C. Correct. The pronoun they makes restorers the subject of the verb allowed, which is logically sound.
我觉得这里的it没有形式主语的功能,此to do 非彼to do。这里的to do是allow的固定搭配,而不是 it is +adj.+ to do的形式,因此这里前面的it只能是allow这个动作的承受者,显然只能是restorers。
-- by 会员 wyw1018 (2012/10/18 23:52:09)
这个解释是非常合理的,但是,可不可以确认下,这真的只能是allow的固定用法吗?也就是说,allow sb./sth.(有生命的) to do sth.是本来的形式,而不存在allow sth.(无生命的) to do sth....并且,因此当被动语态出现的时候,我们不能当做it is +adj.+ to do的形式,而只能当做allow sb. to do sth. 的被动语态。如果我说的是正确的,您有没有其他的例子?看来,这可能是我个人语法的一个弱点啊。多谢!!!
Restorers say that if allowed to remove and replace the discolored layer of varnish on the Mona Lisa, the colors Leonardo da Vinci painted nearly five hundred years ago will once again shine through. A. If B. if it is C. if they are D. when E. when it is