Multiple-choice cloze
For questions 1-8, read the text below and decide which answer (A, B, C or D) best fits each gap.
For most of human history, dreams were as messages, whether from the gods, the dead or the hidden recesses of the mind. Modern sleep research has taken a more sober , but it has not entirely settled the question of what dreams are for. One influential theory holds that dreaming allows the brain to through the day's experiences, strengthening some memories and discarding others. Another suggests that dreams offer a kind of rehearsal, a safe space in which we can practise responding to threats without coming to any real . Neither theory fully for the strangeness of dreams, however: the abrupt changes of scene, the long-dead relatives who appear without explanation, the mundane anxieties about missed trains and forgotten exams. Researchers face an obvious practical difficulty, too. Dreams can only be studied , through the reports of people who have woken up, and memories of a dream tend to within minutes of waking. For this reason, volunteers in sleep studies are often asked to keep a notebook by the bed and down whatever fragments they can before they disappear.
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