example: OG12-14 14. Sunspots, vortices of gas associated with strong electromagnetic activity, (are visible as dark spots on the surface of the Sun but have never been sighted on) the Sun’s poles or equator. (A) are visible as dark spots on the surface of the Sun but have never been sighted on (B) are visible as dark spots that never have been sighted on the surface of the Sun (C) appear on the surface of the Sun as dark spots although never sighted at (D) appear as dark spots on the surface of the Sun, although never having been sighted at (E) appear as dark spots on the Sun’s surface, which have never been sighted on
解释说， sighted is not a completed verb.作者: May2010 时间: 2010-2-19 00:56
有人可以帮解释下么?作者: kathykathie 时间: 2010-2-19 03:52
Participle can be used as a verb or an adjective. My understanding is that , if it is in front of a noun or a pronoun, it usually is an adjective. for exmaple: I have a boring teacher.
Let us go back to the question OG12-14.
Answer B must be wrong. If you replace the underlining phrases with answer B, you will see it.
Answer C, seting aside other problems, the verb sighted in the subordinate clause is in a positive voice, which does not fit the whole sentence. The passive voice should be be sighted.
Answer D, same problem is here. Having been sighted is a passive voice with a perfect progressive tense. So, the completed verb form should be be having been sighted.
Answer E, which I think is fine, should be expressed more clearly if we put the last clause right behind the subject Sunsports.作者: May2010 时间: 2010-2-21 06:02
Thanks, that is helpful.