Have you ever awakened and felt like you couldn't move? If so, it (probable) scared you. You may have thought something terrible had happened to you. Actually, many people have this experience on a regular basis. It (call) sleep paralysis(瘫痪). it sounds scary, it is normal.
Sleep paralysis happens when a person is falling asleep or waking up. As the person falls asleep, his or her body slows down. Usually the person's mind (relax) at the same time, but occasionally the mind stays awake(long) than the body. As a result, the person can be conscious, or aware, but have trouble moving or (speak). Sleep paralysis can also occur as you wake up. Fortunately, the condition rarely lasts for more than a few seconds. (move) and speech soon return to normal.
Some people report unusual experiences during sleep paralysis. They may hear, see or feel things don't exist. At one time, people (think) that ghosts or monsters had entered the room and were holding them down，keeping them from moving. Science has helped us understand that such visions are actually part of sleep paralysis. Now we know that getting too little sleep, taking certain medications(药物), and changing your sleep schedule can cause sleep paralysis. This condition can be scary, but it's just a trick that you mind is playing your body.
