[单项选择]
{{B}}
Sharks{{/B}}
Sharks are amazing fish that have
been around since long before the dinosaurs existed. They live in waters all
over the world, in every ocean, and even in some rivers and lakes.
Sharks and Bony Fish
Unlike bony fish, sharks have no
bones; their skeleton is made of cartilage(软骨), which is a tough, fibrous
substance, not nearly as hard as bone. Cartilage, a strong fibrous(纤维的)
substance, is softer than bone; our nose and ears are made of cartilage. Sharks
also have no swim bladder (unlike bony fish).
{{B}}Size{{/B}}
There are many different species of sharks
that range in size from the size of a person’s hand to bigger than a bus. The
whale shark is the largest fish in the world; the basking shark is the second
largest fish. Fully-grown sharks range in size from 7 inches long (the Spined
Pygmy shark), up to 50 feet long. Most sharks are intermediate in size, and are
about the same size
A. The passage tells us the habitat and migration of sharks.
B. The passage tells us why sharks are dangerous to people.
C. The passage introduces the evolutional process of sharks.
D. The passage introduces the basic information about sharks.