Politicians and pollsters alike warn that the outcome of a presidential race remains __ until Election Day itself, and many races depend on factors that run from bad weather __ voter turnout to last-minute scandals.
A．unknown … abetting
B．unlikely … decreasing
C．fluid … affecting
D．predetermined … consolidating
E．fixed … absorbing
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In the year shown in which the median price of existing homes sold was closest to the median price of new homes sold, approximately how many million existing homes were sold？
A．1.2
B．1.6
C．2.0
D．2.4
E．2.8 -
This thing called love is a total mystery, and the __ of passion and despair that accompanies every romantic devotion may keep one eternally perplexed.
A．coagulation
B．requital
C．admixture
D．instability
E．vagaries -
The passage implies that which of the following steps would be the first performed by explorers who wish to maximize their chances of discovering gold？
A．Surveying several sites known to have been formed more than two billion years ago
B．Limiting exploration to sites known to have been formed from metamorphic fluid.
C．Using an appropriate conceptual model to select a site for further exploration
D．Using geophysical methods to analyze rocks over a broad area
E．Limiting exploration to sites where alluvial gold has previously been found -
According to the passage, the outbreak of dengue hemorrhagic fever in the 1950’s occurred for which of the following reasons？
A．The mosquito Aedes aegypti was newly introduced into Asia.
B．The mosquito Aedes aegypti became more numerous.
C．The mosquito Aedes albopictus became infected with the dengue virus.
D．Individuals who would normally acquire immunity to the dengue virus as infants were not infected until later in life.
E．More people began to visit and inhabit areas in which mosquitos live and breed. -
According to a recent theory, Archean-age gold-quartz
vein systems were formed over two billion years ago from
magmatic fluids that originated from molten granitelike
bodies deep beneath the surface of the Earth. This theory is
（5) contrary to the widely held view that the systems were
deposited from metamorphic fluids, that is, from fluids that
formed during the dehydration of wet sedimentary rocks.
he recently developed theory has considerable practical
importance. Most of the gold deposits discovered during
（10)the original gold rushes were exposed at the Earth’s surface
and were found because they had shed trails of alluvial
gold that were easily traced by simple prospecting methods.
Although these same methods still lead to an occasional
discovery, most deposits not yet discovered have gone
（15) undetected because they are buried and have no surface
expression.
The challenge in exploration is therefore to unravel the
subsurface geology of an area and pinpoint the position of
buried minerals. Methods widely used today include
（20) analysis of aerial images that yield a broad geological
overview; geophysical techniques that provide data on the
magnetic, electrical, and mineralogical properties of the
rocks being investigated; and sensitive chemical tests that
are able to detect the subtle chemical halos that often
（25) envelop mineralization. However, none of these high-
technology methods are of any value if the sites to which
they are applied have never mineralized, and to maximize
the chances of discovery the explorer must therefore pay
particular attention to selecting the ground formations most
（30) likely to be mineralized. Such ground selection relies to
varying degrees on conceptual models, which take into
account theoretical studies of relevant factors.
These models are constructed primarily from empirical
observations of known mineral deposits and from theories
35) of ore-forming processes. The explorer uses the models to
identify those geological features that are critical to the
formation of the mineralization being modeled, and then
tries to select areas for exploration that exhibit as many of
the critical features as possible.
The author is primarily concerned with__
A．advocating a return to an older methodology
B．explaining the importance of a recent theory
C．enumerating differences between two widely used methods
D．describing events leading to a discovery
E．challenging the assumptions on which a theory is based