Do you forget to turn off the lights and heaters when you go out of a room? In 2040 it will not 【B1】. They will turn themselves off—and on again when you return. A sensor will 【B2】 the presence of a human and turn the systems on, and when the humans 【B3】 it will turn them off again. The sensors will work 【B4】 the central home computer, and they will do much more than just turn the fires and lights on and off for you. They will detect 【B5】 electrical appliances, plugs or switches, 【B6】 them so that they cannot harm anyone and then 【B7】 you that they need 【B8】. They will detect fire and if you are out of the house , the computer will call the fire brigade. It will also call the police 【B9】 the sensors detect an intruder (闯入者). This will not be too difficult 【B10】 the locks on the 【B11】 doors will be electronic. You will open them using your 【B12】 card—the one you use for 【B13】 —maybe using a number 【B14】 only to you. The computer will be 【B15】 than a fireman—policeman servant. It will be an entertainer, and most of your 【B16】 will come 【B17】 into your home. It does now, 【B18】 by 2040' entertainment' will 【B19】 much more. For one thing, you will be able to take 【B20】 actively, rather than just watching 【B1】