GWD 6-10,11

The sloth bear, an insect-eating

       animal native to Nepal, exhibits only one

       behavior that is truly distinct from that of

Line       other bear species:  the females carry

  (5)      their cubs (at least part-time) until the

cubs are about nine months old, even

though the cubs can walk on their own

at six months.  Cub-carrying also occurs

among some other myrmecophagous

(10)      (ant-eating) mammals; therefore, one

explanation is that cub-carrying is

necessitated by myrmecophagy, since

myrmecophagy entails a low metabolic

rate and high energy expenditure in

(15)      walking between food patches.  How-

ever, although polar bears’ locomotion

is similarly inefficient, polar bear cubs

walk along with their mother.  Further-

more, the daily movements of sloth

(20)      bears and American black bears—

       which are similar in size to sloth bears

       and have similar-sized home ranges—

reveal similar travel rates and distances,

suggesting that if black bear cubs are

(25)      able to keep up with their mother, so

too should sloth bear cubs.

      An alternative explanation is defense

from predation.  Black bear cubs use

trees for defense, whereas brown bears

(30)      and polar bears, which regularly inhabit

treeless environments, rely on aggres-

sion to protect their cubs.  Like brown

       bears and polar bears (and unlike other

myrmecophagous mammals, which are

(35)    noted for their passivity), sloth bears

are easily provoked to aggression.

Sloth bears also have relatively large

canine teeth, which appear to be more

functional for fighting than for foraging.

(40)     Like brown bears and polar bears,

sloth bears may have evolved in an

environment with few trees.  They are

especially attracted to food-rich

grasslands; although few grasslands

(45)      persist today on the Indian subcontinent,

this type of habitat was once wide-

spread there.  Grasslands support

high densities of tigers, which fight and

sometimes kill sloth bears; sloth bears

(50)      also coexist with and have been killed

by tree-climbing leopards, and are often

confronted and chased by rhinoceroses

and elephants, which can topple trees.

Collectively these factors probably

(55)      selected against tree-climbing as a

defensive strategy for sloth bear cubs.

Because sloth bears are smaller than

brown and polar bears and are under

greater threat from dangerous animals,

(60)      they may have adopted the extra pre-

caution of carrying their cubs.  Although

cub-carrying may also be adoptive for

myrmecophagous foraging, the behavior

of sloth bear cubs, which climb on their

(65)      mother’s back at the first sign of danger,

suggests that predation was a key

stimulus.

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Answer:

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Q11:

Which of the following, if true, would most weaken the author’s argument in lines 18-26 (“Furthermore … sloth bear cubs”)?

C 是SUPPORT 不是WEAKEN。if the home ranges of the black bears are bigger than those of some sloth bears then it means the black bear cubs should move more than the sloth bear cubs do.

D是 WEAKEN : When home ranges and body size are same between sloth bears and black bears,  blacks bears have  a more efficient lomocation than sloth bears do , so that black bear cubs can move more efficiently than sloth bear cubs, 就是说SLOTH BEAR CUBS的运动不如BLACK BEAR CUBS 的运动有效所以需要妈妈背着

刚才没讲清楚， LINE 18~26行中作者是论述SLOTH BEAR CUB 小熊应该不用妈妈背。文章一开始讲了SLOTH BEAR 妈妈背小熊的现象是与其他熊类不同的 并给出一种解释这种现象发生在食虫类熊中。15行 HOWEVER开始转折，先讲与SLOTH BEAR 的LOMOCATION 相同的北极熊就不用妈妈背，18行FUTHERMORE是递进一直到26行 列举了BLACK BEAR 与SLOTH BEAR许多 的相同处并指出BLACK BEAR CUBS 不用妈妈背，18~26的论点是SLOTH BEAR CUBS也应该不用妈妈背。15行HOWEVER 后反驳了第一种解释所以第二段给出另一个解释并证明新解释是对的

11题是逻辑题，定位的方法是不是多用于细节题呀