The computer is a useful machine. It is the most important invention in many years. The oldest kind of computer is the abacus , used in China centuries ago, but the first large, modern computer was built in 1946. A computer then could do maths problems quite fast. Today computers are used in many ways and can do many kinds of work. In a few years the computer may touch the life of everyone, even people in faraway villages. In the last few years, there have been great changes in computers. They are getting smaller and smaller, and computing faster and faster, Many scientists agree that computers can now do many things, but they cannot do everything. Who knows what the computers of tomorrow will be like? Will computers bring good things or bad things to people? The scientists of today will have to decide how to use the computers of tomorrow. The first large, modern computer was built about   _   years ago.
a few forty sixty eighty