J422是结构钢焊条牌号完整的表示方法，其中“42”表示熔敷金属的抗拉强度最大值为4
题型：判断题
问题：
J422是结构钢焊条牌号完整的表示方法，其中“42”表示熔敷金属的抗拉强度最大值为420MPa。( )
题型：判断题
Scientists in Canada say big fish have almost disappeared from the world since the start of
industrial（产业的） fishing in the 1950s. The scientists found the numbers of some kinds of large fish have dropped by ninety percent in the past fifty years.
The study took ten years. The researchers gathered records from fishing businesses and governments around the world. The magazine Nature published the findings.
The scientists say the common method called long line fishing ravages the populations of large fish. This method involves many fishing lines connected to one boat. These wires can be nearly one hundred kilometers long. They hold thousands of sharp metal hooks to catch fish.
Long line fishing is especially common in the Japanese fishing industry. Records showed that Japanese boats used to catch about ten fish for every one hundred hooks. But long line fishing boats now might only catch one fish per hundred hooks.
The scientists say industrial fishing can destroy groups of fish much faster than in the past. The study suggests that whole populations can disappear almost completely from new fishing areas within ten to fifteen years.
Ransom Myers and Boris Worm of Dalhousie University in Nova Scotia led the study with the University of Kiel in Germany. Worm says the destruction could lead to a complete reorganization of ocean life systems. Meyers says the decreased num
bers of large fish are not the only worry. He says even populations that are able to reproduce do not get the chance to live long enough to grow as big as their ancestors. He says not only are there fewer
big fish, but also they are smaller than those of the past.
It’s the end of this program ,Thank you for your listening.
小题1:What’s the best title for the passage?
A．Big fish are disappearing
B．Long—line fishing in Japan
C．The harm of industrial fishing
D．Stop killing big fish小题2:Which of the following DOESN’T show that the populations of big fish are smaller than before?
A．Fish can disappear almost completely from new fishing areas.
B．Now long—line fishing boats might catch one fish per hundred hooks.
C．Fish now don’t have the chance to grow big enough.
D．Scientists spent ten years studying the populations of large fish.小题3:What can we learn from the passage?
A．The number of big fish started to drop greatly about fifty years ago.
B．The study was started by Boris Worm of Dalhousie alone.
C．There will be no big fish left in fifty years .
D．Japaneses people have stopped catching big fish.