英語の長文の和訳をお願いします。
（A）～（C）
アall イanother ウnobody エothers オsome
（D）,（E）
アenough イgood ウtroubled エwell
が入ります。自分で訳した訳に自信がありませんでした。
設問もあわせて、極端な意訳をあまりしないでお願いします。
スペルには十分注意したつもりですが、もし間違っていたらすみません。
Sleep is a natural process, and although a lot has been written about the subject, it is still surrounded by mystery. It is used by（A）as an escape from the world, and regarded by（B）as a irritating waste of time; but（C）can do without sleep completely.
Our night´s sleep does not just consist of a steady phase of gradually deepening sleep. It alternates between two stages: non-dreaming or ordinary sleep, and REM（rapid eye movement）or dreaming sleep.
As soon as we fall asleep we go straight into non-dreaming sleep for an hour or so, then into REM sleep for about 15 minutes, then back into non dreaming sleep. It alternates in this way for the rest of the night, with non-dreaming sleep tending to last longer at the beginning of the night. On-dreaming sleep occupies about three-quarters of our night´s sleep, about a quarter of it deep and the rest fairly light.
It is widely believed that sleep repairs the body and makes good the damage caused by being awake. But its main function is to refresh the brain. Experts believe that probably only about two-thirds of our sleep is necessary for repairing and refreshing the brain, with the most valuable sleep coming in the first few hours of the non- dreaming period: the last few hours of sleep are not so essential. The brain can manage quite well with reduced sleep as long as it is uninterrupted sleep.
The quality of sleep is important. A study conducted in the USA looked at short sleepers, who slept for 5.5 hours on average, and long sleepers, who had 8.5 hours or more. It was discovered after a variety of tests that the long sleepers were poor sleepers, had twice as much REM sleep as the short sleepers, appeared to sleep longer to make up for poor sleep, and did not wake up in the morning refreshed. Similarly, people who sleep deeply are not necessarily getting a better quality of sleep than shallow sleepers. Deep sleepers can feel tired the following days, so six hours of（D）sleep is worth more than eight hours of（E）sleep.
以上です。
お礼
ご回答有難うございます。 重ねて質問させてください。受身の進行形という事は、このbeingは現在分詞になるのですか？現在分詞で、 「I would be amazed to ・・・ the excellent methods.」 と、 「It is being used to learn about sleep.」 を繋げている、という事ですか？