单项选择题

From the passage we learn that ______.

A．it is much cheaper to buy an old patent than a new one
B．products are actually inventions which were made a long time ago
C．an invention will not benefit the inventor unless it is reduced to commercial practice
D．patent experts often recommend patents to others by conducting a search through dead patents
<上一题 目录 下一题>
热门 试题

单项选择题
The passage is mainly about ______.
A．the use of patents
B．the access to patents
C．an approach to patents
D．the application for patents
单项选择题
Which of the following is TRUE according to the passage
A．A patent holder must publicize the details of his invention when its legal period is over.
B．When a patent becomes out of effect, it can be re-patented or extended if necessary.
C．It is necessary for an inventor to apply for a patent before he makes his invention public.
D．One can get all the details of a patented invention from a library attached to the patent office.
相关试题