Ⅵ. 阅读理解（主题：人与自然·动物特征）
Almost all animals need to sleep to stay healthy. But sleeping can be dangerous, because other animals may hunt sleeping animals. To help themselves stay safe, animals have many different ways of sleeping. Some of these ways may surprise you!
Some seabirds can sleep while they are flying. These large birds spend most of their lives over the ocean. They are in danger on the water, but they are safe in the air. They glide(滑行) for many hours without moving their wings up and down. Sometimes they sleep while they are gliding.
A dolphin sleeps with just half its brain at a time. It must stay awake to breathe and to watch out for danger. Dolphins can swim without sleep for two months to stay safe. Ducks sleep with just half their brains too. They often sleep in a line. The ducks at both ends help keep the group safe. They keep one eye open to watch out for danger. The ducks in the middle sleep with both eyes closed.
Seals breathe air, but that doesn't stop them from sleeping underwater. They hold their breath and dive deep to sleep up to twenty minutes at a time. Some fish make their own sleeping bags. They make a big bubble and sleep inside it. It also keeps other animals from smelling them. If an animal hits the bubble, the fish swims away quickly.
()25. Why do animals have different ways of sleeping?
A. To hunt other animals.
B. To keep themselves safe.
C. To surprise other animals.
D. To keep themselves healthy.
()26. How do some seabirds sleep according to the passage?
A. By gliding in the air.
B. By resting in the sea.
C. By flying up and down.
D. By staying in the bubbles.
()27. What animals have the same way of sleeping?
A. Fish and seabirds.
B. Seals and seabirds.
C. Dolphins and seals.
D. Dolphins and ducks.
()28. What will happen if an animal hits the bubble of a fish?
A. The fish will swim away quickly.
B. The fish will stay outside.
C. The fish will make a sleeping bag again.
D. The fish will smell other animals.
()29. What's the structure of the passage? (P1=Paragraph 1, …)