20 The computer is an electronic machine. It is a machine that solves problems as much as you do. As an example, let’s trace the way you would add two numbers. Then, let’s see how a computer would do it.

　　Step1. You collect information. That is, you either see or hear the numbers to be added.

　　Step2. You find a method to solve the problem. In this case, you remember how to do addition.

　　Step 3 You bring together the information (the two numbers), and the method (addition)

　　Step 4 You perform the operation, adding the two numbers.

　　Step5 You report the results of your work, either by writing down the answer or by saying it aloud.

　　All computers go through five similar steps.

　　Step 1 The computer receives information, or data, from the outside. It changes the data into electric language, called input.

　　Step 2 The computer has been given a program contain instructions for solving the problem. The instructions ate found in the storage or memory.

　　Step 3 The computer bring together the data from the input and the instructions from the storage. This is done by the computer’s control.

　　Step 4 The computer goes through the steps of the instructions on the data; this is called processing.

　　Step 5 The computer changes the result from electric language to human language. It presents the results in print or sound, called output.

　　Sometimes the five parts of a computer –input, storage, control, processor , and output—are together in one large unit. Other times they are far apart and connected by wires. Often, large computers have one control and processing unit, with a number of separate memory, input, and output device.

　　What does the passage mainly tell us?

　　A The computer is an electric machine.

　　B Computer solve problems in the same way as people do

　　C How we add two numbers

　　D Computers have five parts together in one unit.