The word them in paragraph 2 refers to .

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 36 to 42.

Action movies are exciting and a lot of fun to watch, but they also involve scenes of great risk and danger. In the language of filmmaking, dangerous actions are called stunts. Who performs these stunts? This work is too dangerous for regular actors. Movie companies usually hire special stunt people to stand in for the actors in scenes that are unsafe.
Movie producers don't like to let actors do their own stunt work. If the actors injure themselves, it can delay the production schedule. Using stunt people also saves time. Most stunt people have years of experience, which enables them to perform their stunts with a minimum of risk. It would take too long to train the actors to perform dangerous scenes safely.

Some people who love the thrill of dangerous sports such as skydiving or rock climbing think it would be easy to work as a stunt person. But it isn't enough to be a risk-taker. Stunt performers also have to know what to do if anything goes wrong.

In addition to risk-taking and meticulous attention to detail and planning, stunt work requires being in top physical condition. Although there are a few training programmes for stunt performers, most provide only an overview of the profession. Normally, the people who attend these programmes already have experience in dangerous sports, rescue work, or the military. So the best way to prepare for a career in stunt work is to train in an area that involves strong physical conditioning and has an element of physical danger.

Modern filmmaking techniques have changed the way some dangerous scenes are filmed. For example, computer-generated images make it possible to show stunts that would be too dangerous or expensive for real stunt people to perform. Computer-generated images are often used today to create big fight scenes, car crashes, and explosions.

However, they are not always the best choice. Many audiences want to see real people perform actual stunts. Also, the rising popularity of made-for-TV movies around the world ensures that there is still plenty for stunt people in the film industry.