As you have noticed, you and a fish are different. Eyelids (眼睑), for example. Even sleep is a difference between you     1     a fish.

As far as scientists can tell, even though it’s hard     2    (study) the brains of fish, fish do sleep in     3     way. They at least rest at times, with a slowdown of their body “machinery”. And that is much like sleep.

For fish brains to relax, eyelids may not     4    (need). Some fish lie near the bottom or top of the sea or lake at night. Others hide     5    (them) in the sand or produce a covering as     6    (protect) against predators (捕食者) while their defense (防御者) are sleeping. And sharks—even the kinds     7     continually swim—still have periods of rest in between periods of activity.

Fish don’t have eyelids or need them. Eyelids help us     8    (human) by keeping our eyes from     9    (get) dry, among other things. But dry eyes are     10    (probable) not a problem for animals living in water.

Sudan is the only male northern white rhino (犀牛) left in the world. That     1     (mean) Sudan, 42, is the last hope for avoiding extinction.     2     (protect) him, officials have placed him under 24-hour armed guard at the OI Pejeta Conservancy in central Kenya. Sudan lives there     3     two female northern white rhinos, Fatu and Najin.

Northern white rhinos,     4     can weigh up to 5,000 pounds, were once plentiful across northern and central Africa.     5     (hunter) have killed thousands of rhinos because of     6     high demand for the animals，horns (角). Rhino horns, believed to have medical effects, are used in     7     (tradition) Asian medicines. More than 1,000 rhinos     8     (kill) in 2014 in South Africa alone and fifty-four rhinos in Kenya, which has a much     9     (small) population.

Sudan, Fatu, and Najin have had their horns     10     (remove) so that they will not be hunted. People hope Sudan and one of the females will be able to have a baby. Sudan is very old, but scientists will not give up hope.

According to the World Wildlife Fund, only about 3,890 tigers are left in the wild. India is home to 70 percent of them, and its role in     1     (make) sure the big cat’s survival can’t be understated. Tiger numbers in India are believed to have dropped from about 40,000 at the beginning of the     2    (nine) century to just 1,800 in the early 1970s, when India launched the conservation program Project Tiger. Kanha was one of the original nine     3     (area) set up under that program.

I am looking at an old friend of mine.

He has been one of my best    1    (friend ) for almost 12 years. He has blessed my life with his loyalty, kindness,     2    (wise) and love since the day when I first met him.     3    doesn’t matter to me that he has four legs instead of two, fur instead of clothes, and barks at me instead of talking to me.

As I watch my friend sleeping    4    the sun, I can’t help    5    (think) of all the goodness he has brought into my life. He has been with me every day through good and bad times. He has always been my protector. He has always reminded me that I am loved and showed me how              6    (love) others at the same time.

My friend has aged far     7    (quickly) than me and had more and more health problems over the years. I am not sure how long we will be together before he     8    (pass) away from this world.

This     9    (wonder) dog has helped me understand that you don’t have to be perfect to be loved and    10    poor health and old age might affect the body but they don’t have to decrease the spirit.

Sudan is the only male northern white rhino (犀牛) left in the world. That     1     (mean) Sudan, 42, is the last hope for avoiding extinction.     2     (protect) him, officials have placed him under 24-hour armed guard at the OI Pejeta Conservancy in central Kenya. Sudan lives there     3     two female northern white rhinos, Fatu and Najin.

Northern white rhinos,     4     can weigh up to 5,000 pounds, were once plentiful across northern and central Africa.     5     (hunter) have killed thousands of rhinos because of     6     high demand for the animals，horns (角). Rhino horns, believed to have medical effects, are used in     7     (tradition) Asian medicines. More than 1,000 rhinos     8     (kill) in 2014 in South Africa alone and fifty-four rhinos in Kenya, which has a much     9     (small) population.

Sudan, Fatu, and Najin have had their horns     10     (remove) so that they will not be hunted. People hope Sudan and one of the females will be able to have a baby. Sudan is very old, but scientists will not give up hope.

Our actions sometimes help other species. When a bridge in Austin, Texas was repaired, engineers added small gaps     1    (run) along the length of its bottom. This made a good home for bats, and soon the bridge was the home of thousands of bats. At first, people were afraid of     2     bats and tried to get rid of them. Now, they have come to value their winged neighbors. The bats are a tourist     3    (attract), and they eat lots of bugs every night.