Almost all animals sleep, but do they dream? We certainly can't ask animals if they dream, but we can at least ________ the evidence that they might. There are two ways in which scientists have gone about this seemingly ________ task. One is to look at their physical behaviour during the various stages of the sleep cycle. The second is to see whether their sleeping brains work similarly to our own sleeping brains.

The story of how we ________ how to look into the minds of sleeping animals begins in the 1960s. Back then, reports began to appear in medical journals describing people acting out ________ in their dreams. This was curious, because during so-called REM sleep(rapid eye movement), our muscles are usually paralysed.

Researchers realised that causing a similar state in ________ could allow them to explore how they dream. In 1965, French scientists Michel Jouvet and J F Delorme found that removing a part of the brainstem, called the pons, from a cat's brain ________ it becoming paralysed when in REM. The researchers called the condition "REM without atonia" or REM-A. Instead of lying still, the cats walked around and behaved aggressively. This hinted they were dreaming of ________ from their waking hours.

________ movement is not the only way of looking into dreams, though. Researchers can now ________ look into the electrical and chemical activities of brain cells in animals while they sleep. In 2007, MIT scientists Kenway Louise and Matthew Wilson recorded the activity of neurons in a part of the rat brain called the hippocampus, a structure known to be involved in the formation and encoding of memories. They first recorded the activity of those brain cells while the rats ran in their mazes. Then they looked at the activity of the very same neurons while they slept. Louise and Wilson discovered similar patterns of firing during ________ and during REM. ________ , it was as if the rats were running the maze in their minds while they were sleeping. The results were so clear that the researchers could infer the rats' precise ________ within their mental dream mazes and map them to actual spots within the actual maze.

Does the behaviour of cats in science experiments actually ________ dreaming? Do rats have any subjective awareness that they' re running their mazes in their minds while they nap? We can say with a reasonable amount of ________ that the physiological and behavioural features of dreaming in humans have now been seen in cats, rats, and other animals. Yet what it's actually like to ________ a dream if you' re not human remains a mystery.

Once upon a time, a Japanese man wanted to rebuild his house. First he had to tear(拆)the walls open. Japanese houses _________ have empty spaces between the wooden walls. As he was tearing them down, he found a lizard(蜥蜴)_________ there because a nail(钉子)from the outside had been _________ into one of its feet. Seeing this, he felt _________ for it, and at the same time wanted to know more about it.

He knew very well that _________ had been knocked into the wall ten years before when the house was first _________. What had happened since then? The lizard had _________ for ten years! To be trapped in a dark wall for ten years without _________—it seems impossible, and is hard to _________. Then he wondered how the lizard could have lived for ten years without moving a single step since its __________ was nailed! So he stopped his work and began to __________ the lizard. He wanted to know what it had been doing, and how it had survived.

A short time later another lizard __________ with food in its mouth. He was __________, and at the same time __________ affected(感动的). Another lizard had been __________ the trapped one for the past ten years.

“What love __________ in this tiny animal! What can love do? It can do __________! Just think, one lizard has been taking care of __________ for ten years, without __________ hope that its partner would be saved,” the man said to himself. If a small lizard can __________ like this, just imagine how we could if we tried.

When Julie got back home from school that afternoon, she noticed a pigeon sitting very closely to the front door of her ________ . It seemed as if the pigeon hadn't moved at all. Julie moved ________, noticing the pigeon had a wound on its left wing. Anxious that a dog or a cat would eat the ________ animal, Julie ran upstairs to tell her mom about the bird.

"We have to help it!" Julie insisted. Whereas Julie's mom made a disgusted face, "I don't want to. Pigeons usually have ________" she said. Julie began to cry. This made Julie's mom feel bad. She ________, but she gave Julie some ________ that the pigeon had to stay in the kitchen in a storage bin. Julie's mom didn't want to touch the ________ bird.

While Julie tried to ________ the bird bits of moist bread, Julie's mom looked online for local animal ________ organizations. She felt silly trying to save an injured pigeon. Finally she found an organization that would ________ the bird, but not until the next morning. Julie stayed up all night ________ the bird.

The next morning Julia and her mother took the ________ to the bird rescue organization. Many people on the train gave Julie and her mother ________ looks. Julie's mother just shrugged. When they ________ the site, the worker welcomed them warmly ________ a big smile, "It's so kind of you to do this. This means ________ to the pigeon!" ________ goodbye to the worker, Julie looked so ________ with a slight flush on her cheeks. On their way home, leaning on her mother' shoulder, Julie said softly, "Thank you, mom, for your support and ________." Julie's mom patted her head, "I'm proud of you, sweetheart. You've taught me ________: Every life deserves to be respected and loved."