Section B
Directions: There are 2 passages in this section．Each passage is followed by some questions or unfinished statements．For each of them there are four choices marked A, B, C and D．You should decide on the best choice.
It is difficult to believe that, only eighty years ago, the idea of the domestic electric light was held in contempt by all the 'experts'—with the exception of a 31-year-old American inventor named Thomas Alva Edison．When the price of gas stocks nosedived in 1878 because Edison announced that he was working on the incandescent(发白热光的) lamp, the British Parliament set up a committee to look into the matter．The distinguished witnesses reported, to the relief of the gas companies, that Edison's ideas were 'good enough for our transatlantic friends, but unworthy of the attention of practical or scientific men.'
The scientific idea being ridiculed is not some wild dream like everlasting motion, but the humble little electric light bulb, which three generations of men bare taken for granted, except when it burns out and leaves them in the dark．Yet although in this matter Edison saw far beyond his contemporaries, he too in later life was guilty of the same shortsightedness that caused trouble to Preece and Co, for he opposed the introduction of alternating current.
The most famous, and perhaps the most instructive, failure in predicting the future has occurred in the fields of aero and astronautics．At the beginning of the twentieth century, scientists were almost unanimous(无异议的) in declaring that heavier-than-air flight was impossible, and anyone who attempted to build aero planes was a fool.
The great American astronomer, Simon Newcomb, wrote a celebrated essay which concluded:
'The demonstration that no possible combination of known substances, known forms of machinery and known forms of force can be united in a practical machine by which men shall fly long distances through the air, seems to the writer as complete as it is possible for the demonstration of any physical fact to be.'
A few years after the first aero planes had started to fly, another astronomer, William H．Pickering, wrote: 'The popular mind often pictures gigantic flying machines speeding across the Atlantic and carrying innumerable passengers in a way equivalent to our modern steamships...It seems safe to say that such ideas must be wholly visionary, and even if a machine could get across with one or two passengers, the expense would be too great for any but the capitalist who could own his own yacht(快艇).'
Of the many lessons to be drawn from these examples is this．Anything that is theoretically possible will be achieved in practice, no matter what the technical difficulties, if it is desired greatly enough.
The word 'nosedived'(Para 1) most probably means '______'.