填空题

When an invention is made, the inventor has three possible courses of action open to him: he can give the invention to the world by publishing it, keep the idea secret, or (36) it.
A granted patent is the result of a (37) struck between an inventor and the state, by which the inventor gets a limited period of (38) and publishes full details of his invention to the public after that period (39) .
Only in the most (40) circumstances is the life span of a patent extended to alter this normal process of events.
A patent remains (41) public after it has terminated. Indeed, patent experts of- ten advise anyone wishing to avoid the high cost of (42) a search through live patents that the one sure way of avoiding violation of any other inventor’s right is to steal and use a dead patent. Likewise, because publication of an idea in any other form permanently (43) further patents on that idea, it is traditionally safe to take ideas from other areas of print. (44)
Anyone closely involved in patents and inventions soon learns that most new ideas are, in fact, as old as the hills. (45) that makes news and money. The basic patent for the theory of magnetic recording dates back to 1886. (46) Even the Volkswagen rear engine car was anticipated by a 1904 patent for a cart with the horse at the rear.