资料题：The author says that in factories（  ）。

There are robots all around us.Some do very complicated jobs like flying airplanes and driving subway trains.And some do one simple job.When an automatic washing machine is switched on, water pours in, the machine waits until the water is hot before washing the clothes.It does this by"feedback" .Information about what is happening is fed back into the robot to tell it what to do next.Our eyes, ears and other senses are our feedback.They tell us what is going on around us.So robots are like people in two ways.They work and they have feedback.But very few robots look like people.Many are hidden away.Robots control the temperature of our houses, our cookers, our hot water systems.We can set the controls lo the temperature we want.The robot does the rest.Its feedback usually comes from a thermostat (恒温器).One kind of thermostat is a strip of metal, which bends when it gets hot.At the right temperature.it bends just enough to work a switch.This turns off the heat.As the air around it cools.the metal straightens, and this tums the heat on again.There are robots all around, making our lives easier.Some of them, like the pocket calculator, can work much more quickly than human beings can.And they rarely make mistakes .In some ways robots are better than people.They work quickly, but do not make mistakes.They do not get bored doing the same job over and over again.And they never get tired.So robots are very useful in factories.They can be taught to do many different: jobs.First their electronic brains must be shown how the job is done.A person moves the robot's " arms"and"hand" through each part of the job.The robot's brain remembers each move.When the robot is put to work on its own, its brain controls the rods, wheels and motors which move its arm.When the robot is needed for a new job, its electronic memory is"wiped clean" .Then it istaught how to do its new task.If the robot's hand stops working, or if something gets in the way, it cannot do the next partof the job.So it stops and signals for help.Then B human engineer attends to the fault.Robots are also used for doing jobs which are dangerous.They can move objects, which aretoo hot or too heavy for people to handle.They can work in places, which are too hot or too coldfor people.And they are not affected by poisonous fumes or gases.The most "intelligent" robots can move and see.Their eyes are cameras.Their metal fingers can feel shapes and even find out how hot and cold objects are.These robots have computer brains, linked to their eyes and fingers, which control their actions.The expensive robots are used in scientific research.They do such jobs as handling radioactive materials.