[求助]请问逗号+AND的用法 - ChaseDream

Unlike
emergency calls that travel through regular telephone lines, where they thus
automatically inform the operator of the location and phone number of the
caller, cellular calls require emergency operators to determine the location of
the caller.

(A)
lines, where they thus automatically inform the operator of the location and
phone number of the caller, cellular calls require emergency operators to
determine the location of the caller

(B)
lines and thus automatically inform the operator of the location and phone
number of the caller, cellular calls require emergency operators to determine
the location of the caller

(C)
lines, thus automatically informing the operator of the location and phone
number of the caller, the location of the caller on a cellular phone has to be
determined by the operator

(D)
lines, and thus automatically inform the operator of the location and phone
number of the caller, emergency operators have to determine the location of the
cellular phone caller

(E)
lines, thus automatically informing the operator of the location and phone
number of the caller, emergency operators receiving a cellular call have to
determine the location of the caller

Developed
by Pennsylvania's Palatine Germans about 1750, they made Conestoga wagons
with high wheels capable of crossing rutted roads, muddy flats, and the
nonroads of the prairie and they had a floor curved upward on either end so as
to prevent cargo from shifting on steep grades.

(A) they
made Conestoga wagons with high wheels capable of crossing rutted roads, muddy
flats, and the nonroads of the prairie and they had a floor curved upward on
either end so as to prevent

(B) they
made Conestoga wagons, which had high wheels capable of crossing rutted roads,
muddy flats, and the nonroads of the prairie, and floors curved upward on their
ends so that they prevented

(C)
Conestoga wagons, with high wheels capable of crossing rutted roads, muddy
flats, and the nonroads of the prairie, and had a floor that was curved upward
at both ends to prevent

(D)
Conestoga wagons had high wheels capable of crossing rutted roads, muddy flats,
and the nonroads of the prairie, and a floor that was curved upward at both
ends to prevent

(E)
Conestoga wagons had high wheels capable of crossing rutted roads, muddy flats,
and the nonroads of the prairie and floors curving upward at their ends so that
it prevented

以下是引用WSMJ在2009-6-2 11:38:00的发言：
问题：1，三重并列是否只能有2个逗号？2，逗号+and后面是否一定要跟完整句子？

(A)
lines, where they thus automatically inform the operator of the location and
phone number of the caller, cellular calls require emergency operators to
determine the location of the caller

(B)
lines and thus automatically inform the operator of the location and phone
number of the caller, cellular calls require emergency operators to determine
the location of the caller

(C)
lines, thus automatically informing the operator of the location and phone
number of the caller, the location of the caller on a cellular phone has to be
determined by the operator

(D)
lines, and thus automatically inform the operator of the location and phone
number of the caller, emergency operators have to determine the location of the
cellular phone caller

(E)
lines, thus automatically informing the operator of the location and phone
number of the caller, emergency operators receiving a cellular call have to
determine the location of the caller

此题仅一步就可以选出正确答案。unlike后面必须马上说出来谁干什么了，而不允许让接收人琢磨，换句话说，凡是逗号后面没有接名词noun，而是代词pronoun的，必错！此原则适用95%GMAT考题。

PREP破解中说，and前面有逗号，后面应该是一个完整的句子。答案是B

(A) they
made Conestoga wagons with high wheels capable of crossing rutted roads, muddy
flats, and the nonroads of the prairie and they had a floor curved upward on
either end so as to prevent

(B) they
made Conestoga wagons, which had high wheels capable of crossing rutted roads,
muddy flats, and the nonroads of the prairie, and floors curved upward on their
ends so that they prevented

(C)
Conestoga wagons, with high wheels capable of crossing rutted roads, muddy
flats, and the nonroads of the prairie, and had a floor that was curved upward
at both ends to prevent

(D)
Conestoga wagons had high wheels capable of crossing rutted roads, muddy flats,
and the nonroads of the prairie, and a floor that was curved upward at both
ends to prevent

(E)
Conestoga wagons had high wheels capable of crossing rutted roads, muddy flats,
and the nonroads of the prairie and floors curving upward at their ends so that
it prevented

AB排除过程参照上题

C那个with恶心，参照上题也可干掉

DE开比，发现E so that it的这个代词又得琢磨，明显不爽，干掉，填D。

答案是D，但是D的结构是xxx had A1 capable of crossing B1, B2, and B3, and A2 that xxxxx.

为什么PREP两条题的解释有矛盾呢？怎么理解呢？

谢谢！！！！