求教OG10-7 已错三遍了。

sunny9653

The ice on the front windshield of the car had formed when moisture condensed during the night.The ice melted quickly after the car was warmed up the next morning because the defrosting vent,which blows on the front windshield,was turned on full force.
Which if the following, if true, most seriously jeopardizes the validity of the explanation for the speed with which the ice melted?
A, The side window with no ice condensation on them.
B, Even though no attempt was made to defrost the back window, the ice there melted at the same rate as did the ice on the front shield.
C, The speed at which the ice on the window melts increases as the temperature of the air blown on the window increases.
D, The warm air from the defrosting vent for the front windshield cools rapidly as it dissipates throughout the rest of the car.
E, The defrosting vent operates efficiently even when the heater,which blows the warm air toward the feet or faces of the driver and passengers,is on.

The key is B.
D为什么不对呢？如果空气变冷了不也影响除霜的速度吗？
请大家指点指点。

sunny9653

多谢楼上二位的指点，终于开窍了！

百草花园

我觉得D有一点支持的意思。既然defrosting vent还没有到the rest of car 就凉掉了，说

明它对 front windshield 作用最大，这就加强了defrosting vent的作用。与B的意思正好相

反

乱草花儿

 D应该是无关项吧，因为是说vent吹的热风随着在车的其他空间中移动而变冷。题目的重点

是vent开到full force，前window就defrost quickly，与vent跟window的关系无关。不知道这

样说对不对

sunny9653

Thanks for your help, nut7910!
but,I am still a little confused.The question is  jeopardizes the validity of the

explanation for the speed with which the ice melted.  I paid more  attention to the

speed.I know B weaken the function of the vent.But,I think D  can weaken the speed

with which the ice melted because D says the warm air cool rapidly.

Do I think too much?I am really suffering from those kind of CR questions.

XIAOYUEHAN

 B很直接的指出有没有vent效果都是一样的，进而削弱了vent的作用