In this unit you will : n learn how we can benefit from research about hearing . n consider the positive and negative effects of gossip . n engage in extended conversations . n learn how to make inferences . At the end of the unit you will be able to : n write a paragraph about the advantages and disadvantages of Facebook . n ask for and give advice in writing . A We are surrounded by different sounds . Write down at least four sounds that you can hear now . Compare your list with a partner . Did you hear the same sounds ? B A decibel ( abbreviated dB ) is the unit used to measure the loudness of a sound . Look at the decibel scale . Then in your notebook , arrange the sounds below according to their decibel level . The empty spaces in the scale will help you . Check your answers on page 174 . rainfall rock concert washing machine city traffic plane tractor C With a partner , answer the questions . Check your answers on page 174 .  אל הספר