GWD 7-24一道很想不通却找不到帖子的题

ericzhang11

Q22 to Q25:

      Earth’s surface consists of rigid

            plates that are constantly shifting and

            jostling one another.  late movements

Line     are the surface expressions of motions

  (5)      in the mantle—the thick shell of rock

that lies between Earth’s crust and its

metallic core.  Although the hot rock of

the mantle is a solid, under the tre-

mendous pressure of the crust and

(10)     overlying rock of the mantle, it flows like

a viscous liquid.  The mantle’s motions,

analogous to those in a pot of boiling

water, cool the mantle by carrying hot

material to the surface and returning

(15)     cooler material to the depths.  When

the edge of one plate bends under

another and its cooler material is con-

sumed in the mantle, volcanic activity

occurs as molten lava rises from the

(20)     downgoing plate and erupts through the

            overlying one.

                  Most volcanoes occur at plate

boundaries.  However, certain “mis-

placed” volcanoes far from plate

(25)     edges result from a second, indepen-

dent mechanism that cools the deep

interior of Earth.  Because of its prox-

imity to Earth’s core, the rock at the

base of the mantle is much hotter than

(30)     rock in the upper mantle.  The hotter the

mantle rock is, the less it resists flow-

ing.  Reservoirs of this hot rock collect

            in the base of the mantle.  When a

reservoir is sufficiently large, a sphere

(35)    of this hot rock forces its way up

through the upper mantle to Earth’s

surface, creating a broad bulge in the

topography.  The “mantle plume” thus

           formed, once established, continues to

(40)    channel hot material from the mantle

base until the reservoir is emptied.

The surface mark of an established

plume is a hot spot—an isolated

region of volcanoes and uplifted terrain

(45)     located far from the edge of a surface

plate.  Because the source of a hot

spot remains fixed while a surface

plate moves over it, over a long period

of time an active plume creates a chain

(50)     of volcanoes or volcanic islands, a

track marking the position of the plume

relative to the moving plate.  The natural

history of the Hawaiian island chain

clearly shows the movement of the

Pacific plate over a fixed plume.

Q24:

The author’s reference to the Hawaiian Islands serves primarily to

                        

provide an example of a type of volcanic activity that does not occur elsewhere

identify the evidence initially used to establish that the Pacific plate moves

call into question a theory about the source of the volcanoes that created the Hawaiian Islands

illustrate the distance from plate edges at which volcanoes typically appear

provide an example of how mantle plumes manifest themselves on Earth’s surface

从最后一句话和前文来看，分明说plumes是不移动的，而是PLATE在PLUMES上面移动，答案怎么会是E呢，虽然B中INITIALLY不好，但也应当比E好啊？不知哪位能点拨一下？

ProteinMonica

首先：作者提到Hawaiian Islands是 example 不是什么evidence ,只剩下 A 和 E,然后理解一下意思，发现A完全文不对题

其次：manifest = to show

其实花点时间把选项读懂这题不难

howcoolya

那什么是evidence？什么是example呢？

我赞成选B。鄙视E这个答案。根本就是错误答案。光看manifest=show，就认定是改写，未免太可笑了吧。