求助：ETS Test code 42 CR Questions...

4. The mastodon, a large mammal resembling today's
elephant, became extinct at the end of the Ice Age.
Scientists once attributed the mastodon's extinction
to the disappearance of evergreen forests at the end
of the Ice Age. More recently, however, scientists
have rejected that theory, hypothesizing instead that
the mastodon's extinction was caused by the
draining of glacial wetlands.

 Which of the following, if recently discovered,
would help to account for the change in the
accepted explanation of the mastodon's extinction?

(A) When the Ice Age ended, many forests died off,
endangering the food supply for herbivores that
fed primarily on evergreens.

(B) As glaciers receded at the end of the Ice Age,
glacial wetlands drained, leaving a new
topography of hills and plains.

(C) Bacteria found in mastodon remains are similar
to bacteria found in the remains of species that
are known to have fed on evergreens.

(D) The mastodon's diet consisted primarily of
water plants such as marsh grasses and water
lilies.

(E) Evergreen forests were inhabited by many
species of large mammals until the end of the
Ice Age.

The key is D...I don't know why...What about C?

14. The recycling of municipal solid waste is widely
seen as an environmentally preferable alternative to
the prevailing practices of incineration and of
dumping in landfills. Recycling is profitable, as the
recycling programs already in operation
demonstrate. A state legislator proposes that
communities should therefore be required to adopt
recycling and to reach the target of recycling 50
percent of all solid waste within 5 years.

 Which of the following, if true, most seriously calls
into question the advisability of implementing the
proposal?

(A) Existing recycling programs have been
voluntary, with citizen participation ranging
from 30 percent in some communities to 80
percent in others.

(B) Existing recycling programs have been
restricted to that 20 percent of solid waste that,
when reprocessed, can match processed raw
materials in quality and price.

(C) Existing recycling programs have had recurrent
difficulties finding purchasers for their
materials usually because of quantities too
small to permit cost-effective pickup and
transportation.

(D) Some of the materials that can be recycled are
the very materials that, when incinerated,
produce the least pollution.

(E) Many of the materials that cannot be recycled
are also difficult to incinerate.

The key is B...I don't know why...

15. A recent survey found that more computers than
copies of computer programs were purchased by
Germans last year. The best interpretation of this
finding is that the practice of illegally duplicating
commercial computer programs is widespread
among Germans.

 Each of the following, if true, would counter some
reasonable objection to the interpretation advanced
above EXCEPT:

(A) Few German computer users write their own
computer programs.

(B) There are few free noncommercial computer
programs available in Germany.

(C) Some Germans purchase computers outside of
Germany for use in Germany, and such
purchases were counted in the survey.

(D) The typical German computer user has several
commercially written computer programs on
his or her computer.

(E) Many Germans legally make duplicates of
commercial computer programs, but such
duplicates were counted as purchased copies in
the survey.

The key is C...I don't understand the question....

Thanks so much.........