题目内容：

When someone says “SHARK” most people think of a big, toothy, underwater animal; basically we are imagining a Great White. In fact sharks come in all shapes, sizes and even colors! Follow me please; I’d like to show you a very special small shark commonly known as horn sharks, only found in the coastal waters of north-west North America.

Look at this shark, and you can easily see the horns on it and you will know the reason why it is called the horn shark is that it has the broad, flattened head and two large horn-like spines(脊椎) found behind its eyes and makes it one of the hardiest of all shark species. What makes it unique is that as its enemy attempts to swallow it, the spines on its back will stick into the enemy’s mouth and give a good chance for it to get away.

The horn shark is brown in color with black spots all over its body. The adults can reach up to a length of 4 feet and weigh up to 10 kg. An interesting fact about the horn shark is that it has five gills(鳃). The horn shark is a clumsy swimmer using its flexible pectoral fins(胸鳍)to push itself along the bottom of the ocean. The maximum distance that has ever been recorded for a horn shark to have traveled out from its habitat is 10 miles.

Today, as so little is known about its population off the Californian coast, they have been listed as being “Data Deficient” in the World Conservation Union. The horn shark is being threatened both by water pollution and commercial fishing in the area. Though they are not among those sea creatures hunted primarily for food, but they often get caught as a by-catch in fishing expeditions.

1.The horn shark gets its name for______.

A. its small size                            B. its large eyes

C. its two large spines                       D. its brown color with spots

2.How is paragraph 3 mainly developed?

A. By giving descriptions                     B. By following time order

C. By analyzing causes                       D. By making comparisons

3.Which factors contribute to the horn shark’s being on the “Data Deficient” list?

①That people like hunting them for pets        ②That people fish them for fun

③Water pollution off the coast                ④Knowing little about them

A. ①②                B.②③            C. ①④            D.③④

4. According to the passage, all of the following are unique to the horn shark EXCEPT that_____.

A. it doesn’t travel far

B. it is good at swimming

C. its spines can be used to attack the enemy and escape

D. it is only found in the coastal waters of north-west North America