Fill in each blank in the following passage with a suitable word. 

The electronic computer is the (01)................... significant invention since the steam engine. While the industrial revolution previously (02)................... the nature of manual work, the computer revolution is now changing the work done by the brain. Nowadays micro-computers are manufactured in hundreds of thousands and are constantly being equipped with more (03)................... more ingenious devices. Contrary to popular belief, computers themselves cannot (04)................... mistakes. The answer will always be correct if the programme fed into the computer is correct.