Do the names Sim City, The Sims, MS Flight Simulator mean anything to you? Well, they are all popular video games that simulate reality. In Sim City, for example, players have to build 1) ..... city that looks and functions' much like a real one', with houses, shops and factories. However, we 2) ..... only use computer simulations for fun. 3) .... are many things that we cannot study or test in real life because it would be too difficult or dangerous. Computer simulations make such study and testing possible. In the past, for example, pilot training used to be very dangerous. Nowadays, pilots can practise their skills before they enter the cockpit² 4) ..... using flight simulators. Engineers 5) ..... use computer simulations to design and test new products before people start using them. They can identify³ dangerous faults in cars and buildings, for instance, and therefore save lives. 1 A one Ba C the 2 A do B have C don't 3 A It B There C They 4 A on B by C from 5 A never B also C too