Last night I had a terrible nightmare. I imagined that I was falling between the walls of a deep valley. I was screaming as the ground rushed towards me. I was sure that I was going to die. Suddenly, I was awake, sweaty but amazingly alive. I was angry with myself.  According to popular stories I am to blame for the bad dream. I had eaten a big piece of cheese before bedtime. Cheese, says folk stories, causes nightmares. One minute I'm eating a piece of cheddar (a kind of cheese), the next _ 'm falling through a canyon  . It's not just folk stories that suggests Roquefort and Red Leicester (two types of cheese) give you nightmares. Scientists seem to agree. Cheese contains a substance that makes our bodies produce a chemical called serotonin. Serotonin slows down the heart and so our blood slows down around our bodies. When we're awake, this can lead to headaches. When we're asleep this gives us strong dreams. Cheese is also hard to digest and may make us sleep badly. We are more likely to wake during deep sleep and remember any dreams or nightmares. Don't think that removing cheese from your late night meals will stop the nightmares. Bananas, chocolate and tomatoes all have the same effect. I'm falling through a canyon suggests that the author is   _  .
falling into a deep valley taking part in an exciting sport dreaming a terrible dream trying to wake up suddenly