题目内容：

Scientists warn today that the Atlantic bluefin tuna（金枪鱼）faces disappearance unless certain action is taken. They used electronic ways to track the movement of the powerful fish from the Gulf of Mexico to the Mediterranean, and report today in the journal Nature that meals of sushi and sandwiches with tuna worldwide are more dangerous than anyone has imagined.

The bluefin tuna can live for 30 years, grow to three metres in length and weigh as much as 700kg. A good one can fetch as much as £ 52,000 in the Tokyo fish markets. “In my lifetime, we’ve brought this big fish to the doorstep of death in the western Atlantic Ocean,” said Barbara Block of Stanford University in California. “The electronic way of tracks provides the best scientific information we’ve ever had to manage these tuna and we must, as an international community, start to act actively to make sure of the future of this fish. ”

Scientists have repeatedly said that the harvest of the seas cannot be as good as before. There are fewer and fewer fish in around Newfoundland, North Sea and Iceland, so fishermen have pushed further offshore in search of deep ocean fish. Tuna—in the Mediterranean and Japan—have been under increasing pressure for years. The International Commission on the Conservation of Atlantic Tuna has tried to manage the fish since 1969．There are two populations: a western one that has dropped by 80% in the past 30 years, and a larger, eastern population. Although catches are controlled by 3,000 tons a year in the western fishery, and 32,000 in the east, no one knew whether the limits worked.

So Professor Block and her team placed tracks on hundreds of the fish and tracked them to depths of more than 900 metres and on journeys of thousands of miles, measuring the movement, body and water temperatures. “There are two ways to save the Atlantic bluefin tuna—protect them in their production grounds and in their feeding grounds,” Prof. Block said. “This will need immediate action in both the central Atlantic, to reduce the loss of the big fish while hunting, and in the Gulf of Mexico and Mediterranean, where tuna produce as separate populations. ”

1. The bluefin tuna in this passage mainly refers to the one _______.

A．in the Atlantic	B．in the Pacific
C．in the Gulf of Mexico	D．in the Mediterranean

2.Which of the following is NOT true according to this passage?

A．The bluefin tuna is a kind of large and heavy fish.

B．The number of the bluefin tuna in the sea is getting smaller and smaller.

C．Scientists are worried about the future of the tuna.

D．Scientists think that the harvest of the seas will remain good.

3.According to Professor Block, tuna can be saved by ______.

A．finding a new way to protect them

B．controlling the catches of them

C．reducing the population to eat them

D．protecting them in their production and feeding grounds

4.The purpose of the passage is to ______.

A．tell people a new way has been found to save the bluefin tuna

B．call for action to save the bluefin tuna

C．warn people not to eat tuna sandwiches anymore

D．help scientists to find a new way to save the bluefin tuna