以下是引用linlin315在2003-8-16 19:51:00的发言: D. than those that can be detected,这个选项用those也没有错因为that can be detected by ground based instruments.可以是好几种光。
this interpretation is quite dangerous. it seems that in Gmat grammar "those" cannot refer to the plural of former single object. thus, it is possible that this somewhat flawed question might have misled you. not worthy.
First of all, in GMAT, you can never say something like "The light of this object is not as bright as those of other objects". It is wrong. The singular or plural form has to agree. So the above sentence should be "The light of this object is not as bright as that of any of the other objects".
In this sentence, "those" can only refer to "source" because "twenty times fainter" follows "source" closely. So even if you change it to "that that can be detected...", "that still refers to "source". I agree with Merlion.
以下是引用merlion在2003-8-16 8:53:00的发言: 我的理解 ... capture light from source [(which is) twenty times fainter than those that can be detected by a third the price of ...], 后面的从句修饰source, source 和source比.
mindfree, i am still confused.
If those refer to sources, the sentence shall be expressed as :
capture light from source twenty times fainter than from those that can be detected by a third the price of
If you are comparing source to source, of course no "from". And it is exactly the same structure of my example.
If you are comparing light to light, you need "from" as there will be a "light" or "that" in front of the "source". The light from this source is darker than that from the other source. You can not just use a "from" there. It is just not right.