JarvisR wrote:
By 1999, astronomers
had discovered 17 nearby stars that are orbited by planets about the size of Jupiter.
(A)
had discovered 17 nearby stars that
are orbited by planets
(B)
had discovered 17 nearby stars with planets orbiting them that
were (C)
had discovered that there were 17 nearby stars
that were orbited by planets
(D) have discovered 17 nearby stars with planets orbiting them that are
(E) have discovered that 17 nearby stars are orbited by planets
First glanceThree answers begin with had discovered; the other two begin with have discovered. Which one is the correct verb tense for this sentence?
Issues(1) Verb: have discoveredHad discovered is the past perfect tense, used to signal that something took place before something else in the past.
Have discovered is the present perfect tense, used to denote something that started in the past but is still true or still ongoing in the present.
The time marker by 1999 indicates that the action took place prior to 1999. As such, the past perfect tense
had discovered is correct: prior to 1999, the astronomers had discovered these stars. Eliminate answers (D) and (E).
(2) Modifier: thatMeaningIt is difficult to choose from among the remaining three choices;
this is one of the hardest problems in the Official Guide. Compare the three choices to find the differences:
(A) …17 nearby stars that
are orbited by planets…
(B) …17 nearby stars with planets orbiting them
that were…
(C) …
there were 17 nearby stars
that were orbited by planets…
Each of these choices presents a reason not to like it…yet one must be the correct answer! Examine each choice in turn.
The opening part of the sentence uses past perfect, so is it okay to switch to present tense, as choice (A) does?
Past perfect does require either a past time marker or a simple past verb—but the sentence does correctly provide the time marker by 1999. The
are verb, then, is not required to be in the past tense. Does it make sense to have a present tense verb at this point in the sentence? What if it said
were?
Astronomers had discovered 17 nearby stars that
are orbited by planets…
Astronomers had discovered 17 nearby stars that
were orbited by planets…
In the first sentence, the stars were orbited by the planets at the time of discovery and they still are today. That meaning is acceptable.
In the second sentence, the stars were orbited by the planets at some point in the past. Was this still happening at the time of the discovery? Or maybe the astronomers discovered something that was true only prior to the discovery? Or perhaps the action was still occurring at the time of discovery but is no longer going on today? The choice of were makes the meaning ambiguous; it’s actually better to use
are. Leave choice (A) in.
Choice (B) contains the noun modifier
that were about the size of Jupiter. What
were about the size of Jupiter: the
stars or the
planets? And when were they the size of Jupiter?
Noun modifier rules dictate that
the modifier be placed as close as possible to the noun that it modifies. In this case, the pronoun
them (referring to
stars) is closest to the word that. The rules allow, however, for an exception: if another noun modifier also modifies the same noun (for instance,
the box of nails,
which is on the table…), then you can have two modifiers in a row, each of which refers back to the original noun. So the
that modifier could also refer to the
planets. It’s impossible to tell whether the
stars or the
planets are
about the size of Jupiter. Answer (B) also introduces ambiguity: when were the stars or planets the size of Jupiter? At the time of discovery? Before? Did they change size later on? Eliminate choice (B) for modifier and meaning issues.
Examine choice (C): The astronomers
had discovered that there were 17 nearby stars. When were those stars present? Prior to the discovery? At the time of discovery? What happened later in time—did they disappear? Further,
that were orbited creates the same ambiguity: was this true prior to the discovery only, or at the time of the discovery, or at some point after? Did the planets implode? Get pulverized by a meteor? Or maybe the stars were the ones to disappear? Or possibly they are all still there today. Eliminate choice (C) for ambiguity.
The Correct AnswerCorrect answer (A) employs the past perfect
had discovered to indicate something that took place
by 1999. Further, the modifier and verb choices indicate clearly that the 17 stars continue to be orbited by Jupiter-sized planets today.
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