Listen to the following passage. Altogether the passage will be read to you four times. During the first reading, which will be

From artificial lights to late-night TV and now our smartphones, / modern life is often blamed for ruining our sleep./ But a recent study in the United States suggests/ our ancestors didn’t get any more sleep than we do./ The researchers monitored societies where people lived like ancient hunter-gatherers. / They found they slept on average six and a half hours a night./ Surprisingly, natural light didn’t have as big an influence as was thought./ Most people fell asleep hours after sunset. / However, temperature was important and the morning’s coldest point / was when most people woke up.