[概括大意] It is often thought that science fiction is a fairly new development in literature， but its ancestors can be found in books written hundreds of years ago. These books were often concerned with the presentation of some form of ideal society， a theme which is still often found in modern stories.
The main idea of this paragraph is__________.
A、Science Fiction is a Fairly New Development in Literature
B、Origins of Science Fiction
C、The Theme of Science Fiction
D、Science Fiction Has a Short History
[填句补文]Doctors believe that secondhand smoke may cause lung cancer in people who do not smoke because nonsmokers often breathe in the smoke from other people‘s cigarettes.________. The US Environmental Protection Agency reports that about 53，000 people die in the United States each year as a result of exposure to secondhand smoke.
A、The risk is even higher for children who live in homes where both parents smoke.
B、In the United States，nine million children under the age of five live in homes with at least one smoker.
C、This smoke is called secondhand smoke.
D、No one knows for sure why Mr. Gilson has lung cancer.