题目内容：

Many of us have had this experience: we lie down in a bed other than our own, perhaps at a friend’s house or in a hotel room, and find it difficult to fall asleep. Is it because the bed is uncomfortable? Maybe, but perhaps there can be other reasons.

According to a new study published in Current Biology, a significant reason is what the scientists call “first night effect”. They believe that one side of the brain acts as a “night watch” to warn us about potential (潜在的) dangers. It forces us to stay awake on the first night in a new environment.

For the study, 35 young volunteers were told to sleep in a lab for several days. Meanwhile, researchers watched their brain activities.

According to the researchers, on their first night, the left brains were more active than the right brains and people had a hard time sleeping. However, left-brain activity reduced as days went by, falling even to the point of complete calm. In this process, the volunteers got an increasingly better sleep experience.

The findings suggest that the different rhythms (节奏) of the sides of the brain influence our sleep. When the two sides work differently, the balance between them is broken. Thus, the brain can’t relax and is sensitive to anything strange in the surroundings, just as it is in the daytime.

“At some level, the brain is continuing to analyze(分析) things, even though you don’t realize the analysis,” US professor Jerome Siegel told Smithsonian Magazine. “If something unusual happens – if a door opens or you hear a key in a lock – you can be alert (警惕的).”

More surprisingly, this situation is similar to the way some animals sleep. Whales, dolphins, and many birds can sleep with half of their brain while the other half stays awake.

If you have ever had what you think is “first night effect”, researchers suggest that you bring your own pillow or sleep in a room similar to your bedroom next time you sleep away from home.

1.can’t you get to sleep?
Introduction	    People can’t fall asleep2.when staying in a new environment.
Reason	    One side of the brain stays awake to warn us about potential (潜在的) dangers.
Process and findings of the3.	    Researchers told some  4. to sleep in a lab to watch their brain activities.     Too many left-brain activities 5.the bad sleep experience on the first night.     Their left brains became 6.active as time went by and became calm gradually.
Explanations to findings	    Whether you can have a good sleep 7.on the balance between the two sides of the brain.     You yourself don’t realize it,8.your brain doesn’t stop analyzing things.     It’s surprising to find out that the way humans sleep is just9. some animals do.
10.	    Take a pillow or live in a similar room when staying in a new place.