阅读下面的短文，在空白处填入适当单词，或填入括号中所给单词的正确形式（每空不多于3个单词）
The first robots were invented in the1920s. Since then robots ____ (appear) in many American films. In some films, they are stronger, faster and cleverer ____ people.
In real life, robots are ____ (main) used in factories. They do some dangerous and difficult jobs for humans.
Robots also help disabled(残疾的) people, for example, blind people. Today many blind people have a guide dog ____ (help) them. In the future, guide dogs might be robot dog.
One kind of robot guide dog has ____ (wheel). It moves in front of the owner. It is very clever. It knows the speed of its owner's walk. The owner ____ (wear) a special belt(带子). This belt sends instructions ____ the owner from the dog, such as "Stop here", "Turn left" or "Turn right".
In the United States, another kind of robot helps disabled people to take care of ____ (them) in their daily life. The robot hears the sound of its owner's voice. It follows instructions such as "Turn the page" or "Make a cup of coffee".
Robots are also used in American hospitals. They can do simple jobs. At one hospital, for example, a robot takes meals from the kitchen to patient's rooms. It ____ gets lost because this robot has a map of the hospital in its computer memory.
____ robots can help people in many ways, they will never take the place of humans.
