"A dead patent" is one that ______.

单项选择题It can be inferred from the passage that ______.

单项选择题The new era of television is brought about by ______.

单项选择题The author of this passage is most probably ______.

单项选择题From the passage we might get the hint that ______.

单项选择题At the very beginning, the author seems to suggest that ______.