After a long day at work, nothing is better than a good (23) __________!Just like on the Earth, in space an astronaut goes to bed at a certain time, then wakes up and prepares for work again. There are a few differences though. Space has no "up" or "down," but it does have microgravity. As a result, astronauts are weightless and can sleep in (24) __________ orientation. However, they have to attach themselves so they don"t float around and bump into something. Space station crews usually sleep in (25) __________ bags located in small crew cabins. Each crew cabin is just big enough for one person. Generally, astronauts are scheduled for eight hours of sleep at the end of each mission day. ‎(26) __________on the Earth, though, they may wake up in the middle of their sleep period to use the toilet, or stay up late and look out of the window. Different things such as excitement or motion sickness can disrupt an astronaut"s sleep pattern. Some astronauts have (27) __________having dreams and nightmares. A. described B. reported C. showed D. presented