20 < 3 1. transform the sentences into negative and interrogative. by the time mum came home her son had cooked the dinner. sandra had been writing a report for three hours before she realized it was too late. this bridge was built in 1953. tom was reading a very interesting book while his dad was watching a football match

mobile phones ,keeping fit

mobile phones entered our life not long ago, but today we can’t imagine our life without them. some doctors say that they are very harmful to the health, especially to the health of children.

the mobile phones emit electromagnetic radiation, and a number of different scientific institutes claim that this radiation is really very harmful, though still there is no hard evidence that showed that mobile phones caused harm in real humans. i try to talk over my mobile phone as less as possibleto avoid the health risks.

they saidthat the bookwas translated from germanin 1989.