27．Why did huge sea scorpions exist for a long time?

A．They were larger than any other animals.

B．There was enough water for them to drink.

C．They knew well how to protect themselves.

D．Fish with large teeth only appeared many years later.

28．What does the author mainly tell us in the text?

A．Sea scorpions were the rulers of Earth before dinosaurs appeared.

B．The fossils of bugs discovered in Germany make scientists puzzled.

C．A sea scorpion was able to grow eight feet long 400 million years ago.

D．The fossils of a sea scorpion's claw show that huge bugs lived long ago.

　　　　　　　　　　　　　　　　C

Lions communicate with each other through body language， touch, smell, and sound. Lions from the same pride(狮群) greet each other by touching their faces, necks and bodies together.

Lions have many scent glands (臭腺) on their faces, lips, foreheads and tails (尾巴). A lion's scent communicates with other lions where they have been and how long ago. They also use scent to attract a friend. Lions have an extra smell organ (器官) called the Jacobson's organ that is used to smell other cats. In order to use this organ, a lion shuts off his nose，and tastes the air through his mouth!

Lions use many parts of their bodies to communicate their feelings through posturing. Because their most dangerous weapons (武器) are their teeth，the most important body part used to communicate is their face. When lions feel threatened and are scared, they show their weapons, raise their tails and lift their backs trying to look as big as possible. The king of the pride will walk with his head held high, his ears standing upright, his mouth closed, and his tail waving from side­to­side. The other members of the pride will walk with their heads held low, their mouths open, and their teeth showing. A lion is able to notice even the slightest change in posture of another lion.

The lion is the loudest of all big cats.Because lions are one of the most threatening animals in the wild, they are not scared to be noisy. Loud roars help keep kings of different prides away from one another. Mothers and their young use the largest variety of calls to communicate because they are the members of the pride that spend the most time together.

29．By smelling a lion can know ________.

A．if there are other lions around him

B．how many lions are in the pride

C．where he can find weapons

D．where a lion will go

30．Which of the following behaviors is friendly?

A．Smelling each other.

B．Touching each other.