Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrases that best fits each of the numbered blanks.

Ever since it was first possible to make a real robot, people have been hoping for the invention of a machine that would do all the necessary jobs around the house. If boring and repetitive factory work could be (1) by robots, why not boring and repetitive household chores too? For a long time the only people who really gave the problem their attention were amateur inventors And they came up against a major difficulty. That is, housework is (2) very complex. It has never been one job it has always been many. A factor robot carries (33) one task endlessly until it is reprogrammed to do something else. It doesn’t run the whole factory. A housework robot on the other hand, has to do several different types of cleaning and carrying jobs and also has to cope with all the different shapes and positions of rooms, furniture, ornaments, cats and dogs. (4), there have been some developments recently. Sensors are available to help the robot locate objects and avoid obstacles. We have the technology to produce the hardware. All that is missing the software - the programs (5) will operate the machine.