求教各位NN:

Highway Official: When resurfacing our
concrete bridges, we should use electrically conductive concrete (ECC) rather
than standard concrete. In the winter, ECC can be heated by passing an electric
current through it, thereby preventing ice buildup. The cost of the electricity
needed is substantially lower than the cost of the de-icing salt we currently
use.

Taxpayer: But construction costs for ECC
are much higher than for standard concrete, so your proposal is probably not
justifiable on economic grounds.

Which of the following, if true, could best
be used to support the highway official’s proposal in the face of taxpayer’s
objection?

A.     The
use of de-icing salt causes corrosion of the reinforcing steel in concrete
bridge decks and damage to the concrete itself, thereby considerably shortening
the useful life of concrete bridges.

B.    
Severe
icing conditions can cause power outages and slow down the work of emergency
crews trying to get power restored.

C.    
In
weather conditions conducive to icing, ice generally forms on the concrete
surfaces of bridges well before it forms on parts of the roadway that go over
solid ground.

D.    
Aside
from its potential use for de-icing bridges, ECC might also be an effective
means of keeping other concrete structures such as parking garages and airport
runways ice free. 

E.      If ECC
were to be used for a bridge surface, the electric current would be turned on
only at times at which ice was likely to form.

TAXPAYER反对的理由就是不经济，所以肯定要找出ECC相对于普通水泥更便宜的新的证据，A是个新的证据。

E）只是讲ECC更加省电而已，表面看是为官员找了证据，但是证据太弱，为什么呢？因为通电本来就比用盐划算，这个没有遭到TAXPLAYER的攻击，进一步强化这个也不能反驳TAXPLAYER，而是需要找到全新的更有利的证据，例如A的用盐会腐蚀桥梁，缩短桥梁的使用寿命

A其实是和cost有关系的，如果桥要重建的话是不是成本会更高?

E中，说的是省电，但是题目讨论的是建设成本，跟使用成本不一样的。