单选题（北京航空航天大学2010年试题） When an invention is made, the inventor has three possible【1】of action open to him; he can give the invention to the world by publishing it, keep the idea【2】, or patent it. A【3】patent is the result of a bargain【4】between an inventor and the state, but the inventor gets a limited period of monopoly and publishes full details of his invention to the public after that period【5】. Only in the most exceptional circumstances【6】the lifespan of a patent【7】to alter this normal process of events. The longest extension ever【8】was to Georges Valensi; his 1939 patent for color TV receiver circuit was extended until 1971 because for most of the patent's normal life there was no color TV to【9】and thus no hope for reward for the invention. Because a patent remains permanently【10】after it has terminated, the shelves of the library attached to the【11】office contain details of literally millions of ideas that are free for anyone to use and, if【12】than half a century, sometimes even re-patent. Indeed, patent experts often advise anyone【13】to avoid the high cost of conducting a search through【14】patents that the one sure way of violation of any other inventor's right is to plagiarize a dead patent. Likewise, because publication of an idea in any other form【15】invalidates further patents on that idea, it is traditionally【16】to take ideas from other areas of print. Much modern technological advance is【17】on these presumptions of legal security. Anyone closely【18】in patents and inventions soon learns that most "new" ideas are, in fact, as old as the hills. It is their reduction to commercial practice, either through necessity or dedication, or through the availability of new technology,【19】makes news and money. The basic patent for the theory for magnetic recording dates back to 1886. Many of the original ideas behind television originate【20】the late 19th and early 20th century. Even the Volkswagen rear engine car was anticipated by a 1904 patent for a cart with the horse at the rear.

【正确答案】 D

【答案解析】解析：空格所在句子大意为：按照契约，发明者可以对自己的成果在一定期限内享有垄断权，垄断——后，他就得把发明的整个细节公之于众。各个选项的意思为：terminating“终止，结束”；continuing“继续”；continues“继续”；terminates“结束，终止”。after后为时间状语从句，所以空格处应填一个动词做从句的谓语。根据句意和各个选项的意思可知，正确答案是D。

【正确答案】 C

【答案解析】解析：空格所在句子大意为：只有在极为特殊的情况下，才可以——专利期限，从而改变这种正常的程序。本题考查选用extend“延长，延伸，扩展”的哪一种形式。这里的主语是the life span of a patent，显然是专利期限被延长，因此使用被动语态，is被提前句子倒装，剩下的就是过去分词extended。根据句意和各个选项的意思可知，正确答案是C。

【正确答案】 C

【答案解析】解析：空格所在句子大意为：1939年他就取得了彩色电视接收器线路的专利，而且这一专利一直延续到1971年，因为这项专利在其大部分正常期限内都没有彩电可供——，因此这项专利就无望获得回报。各个选项的意思为：receiving“止在接收”；sending“正在发送”；receive“接收”；send“发送”。根据句意和各个选项的意思可知，正确答案是C。

【正确答案】 D

【答案解析】解析：空格所在句子大意为：实际上，专利专家们常对——开发有效专利而又想避免高额费用的人提出建议，避免侵犯他人专利权的有效方法就是使用过期专利。空格后的内容作anyone的后置定语，而anyone是动作的发出者，故应选择现在分词形式。根据句意和各个选项的意思可知，正确答案是D。

【正确答案】 A

【答案解析】解析：空格所在句子大意为：实际上，专利专家们常对希望开发—一专利而又想避免高额费用的人提出建议，避免侵犯他人专利权的有效方法就是使用过期专利。各个选项的意思为：live“有效的”，live patent表示“有效专利”之意；dead“无效的，失效的”；working“起作用”；recording“记录的”。根据旬意和各个选项的意思可知，正确答案是A。