Q21:

Editorial:  The roof of Northtown Council’s equipment-storage building collapsed under the weight of last week’s heavy snowfall.  The building was constructed recently and met local building-safety codes in every particular, except that the nails used for attaching roof supports to the building’s columns were of a smaller size than the codes specify for this purpose.  Clearly, this collapse exemplifies how even a single, apparently insignificant, departure from safety standards can have severe consequences.

A   The only other buildings whose roofs collapsed from the weight of the snowfall were older buildings constructed according to less exacting standards than those in the safety codes.
B    Because of the particular location of the equipment-storage building, the weight of snow on its roof was greater than the maximum weight allowed for in the safety codes.
C   Because the equipment-storage building was not intended for human occupation, some safety-code provisions that would have applied to an office building did not apply to it.
D   The columns of the building were no stronger than the building-safety codes required for such a building.
E   Because the equipment-storage building was where the council kept snow-removal equipment, the building was almost completely empty when the roof collapsed.

FAINT~~看了老长时间,看出A来了~~

我认为选A~~A的意思是说其他按照这个standards来的都没有倒塌,也就是非因非果的加强,所以A正确啊~