单选题 The pleasures which a movie offers to our eyes have been paid for with the loss of sight of a man whose name is hardly known outside the annals of science—Joseph Plateau, a Belgian professor, born in Brussels in 1801.
He studied the mechanism of sight, beginning a series of most dangerous experiments at the age of 28 by staring into the sun for 25 seconds to see what the effect on his eyes would be. He was blind for nearly a month. But he went on experimenting, increasing the length of time during which he looked into the sun, knowing that in the end this would cost him his sight. At the age of 42 he was completely and incurably blind; the sun had destroyed the retina (视网膜) of his eye. But he continued to work as well as he could until he died at the age of 82.
Science profited enormously from his research. He studied the so-called "inertia of the eye" (视觉暂留) which makes a picture remain on the retina for about one-sixth of a second after it has disappeared from our vision. This means that, if we see a succession of individual pictures each of which appears only for a fraction of a second, they "overlap" in our brain; and if they show Consecutive phases of movement, that movement will appear to us to be continuous.

单选题 Plateau"s experiments were the first step leading to the invention of ______.

单选题 The result of Plateau"s first experiment was that ______.

单选题 A picture remains on the retina for ______.

单选题 The images that we see are recorded in ______.

单选题 Motion pictures ______.