GWD-4-37

prfdu2005

    

It can be inferred from the passage that
which of the following is an accurate physical description of typical
low-surface-brightness galaxies?

    

 

    

1. They are large spiral galaxies containing fewer stars than do
        conventional galaxies.
2. They are compact but very dim spiral galaxies.
3. They are diffuse spiral galaxies that occupy a large volume of
        space.
4. They are small, young spiral galaxies that contain a high
        proportion of primordial gas.
5. They are large, dense spirals with low luminosity.

答案是C,可A 不对吗？NN们可以帮帮我吗？

顾风

有个小建议，问阅读问题的时候可以把原文粘贴上来，这样方便大家讨论

prfdu2005

谢谢斑斑建议，我知道了

 In addition to conventional

    

         galaxies,
the universe contains

    

         very
dim galaxies that until

    

Line         recently went
unnoticed by

    

  (5)       astronomers.  Possibly as

    

numerous as
conventional gal-

    

axies, these
galaxies have the

    

same general
shape and even

    

the same
approximate number

    

(10)         of stars as a common
type of

    

conventional
galaxy, the spiral,

    

but tend to be
much larger.

    

Because these
galaxies’

    

mass is spread
out over

    

 (15)       larger
areas, they have far

    

fewer stars per
unit volume

    

than do
conventional galaxies.

    

Apparently these low-surface-

    

brightness galaxies, as they

    

 (20)       are
called, take much longer

    

         than
conventional galaxies to

    

         condense
their primordial gas

    

and convert it
to stars—that is,

    

they evolve much
more slowly.

    

 (25)             These galaxies may

    

constitute an answer
to the long-

    

standing puzzle
of the missing

    

baryonic mass in
the universe.

    

Baryons—subatomic
particles

    

 (30)       that
are generally protons or

    

neutrons—are the
source of

    

stellar, and
therefore galactic,

    

         luminosity,
and so their numbers

    

can be estimated
based on how

    

 (35)
                luminous galaxies are.  How-

    

ever, the amount of helium

    

in the universe, as measured

    

by spectroscopy, suggests

    

       that there are far more baryons

    

 (40)      in the universe than estimates

    

based on
galactic luminosity

    

indicate.  Astronomers have

    

long speculated
that the missing

    

baryonic mass
might eventually

    

 (45)       be
discovered in intergalactic

    

space or as some
large popu-

    

lation of
galaxies that are difficult

    

to detect.

It can be inferred from the passage that
which of the following is an accurate physical description of typical
low-surface-brightness galaxies?

    

 

    

1. They are large spiral galaxies containing fewer stars than do
        conventional galaxies.
2. They are compact but very dim spiral galaxies.
3. They are diffuse spiral galaxies that occupy a large volume of
        space.
4. They are small, young spiral galaxies that contain a high
        proportion of primordial gas.
5. They are large, dense spirals with low luminosity.

答案是C,可A 不对吗？NN们可以帮帮我吗？

lyj851011

A中的"containing fewer stars than do conventional galaxies"不对吧.

原文中的是"they have far fewer stars per unit volume than do conventional galaxies".