A、It will be long before robots can be used at home. B、It will be very expensive to use robots in the future. C、Robots will take

We are now living in a world in which robots are taking over much of the work. Robots make our cars, fly our planes and work out wages.
    But these robots are not mechanical men and women. They do not look like us. They are machines specially built to do some of the things that human beings can.
    Although they may not look like us, robots need some human features in order to be able to do human work. First of all they need some kind of brain. Their brain" is a computer, which has a memory to remember instructions and the ability to control other equipment. Another essential feature of many robots is an arm that can do the kind of things that human beings can with their arms. One-armed robots are now coming into widespread use in industry. They are being used, for example, on car assembly lines.
    The great advantage of robots over human workers is that they can work non-stop for long periods. They never get tired, and always work with the same accuracy. They can also work in conditions that humans could not bear. Last but not least, as more robots are built, their cost will come down.
    Although robots are rapidly taking over many jobs in industry, they seem a long way from taking over in the home. The problem is that it would take a very complex and costly robot to perform half the tasks involved in housework.
19 According to the speaker, what can the present-day robots do?
20 What do we learn about the "brain" of robots?
21 What is the great advantage of robots over human workers?
22 What does the speaker tell us about the future of robots?