[填空题]

Cancer experts now believe that up to ______ of all cancers come from lifestyle factors such as smoking, diet and lack of exercise.

[单项选择]Many experts now believe that even if all space littering were to stop completely, the number of stray objects would continue to increase for centuries. The reason : debris is now so dense that objects will continue to crash into each other, creating even more objects, expanding the rubbish cloud geometrically. "We’ve been saying for years that these things are going to happen," says Nicholas Johnson, head of NASA’s Orbital Debris Program Office. "Until they happen, it’s hard to get people’s interest. "
What seems to best describe Nicholas Johnson’s attitude towards what has happened
A. He is happy that people are starting to pay attention to the problem.
B. He is critical that people have not paid enough attention to the problem.
C. He is objective when commenting on the problem of cosmic junk.
D. He is supportive to what people have done to deal with the problem.

[填空题]Why do patent experts believe it is traditionally safe to take ideas from other areas of print

[单项选择]Passage ThreeWhat do the experts believe will happen by the year 2050
A. The sea level will be 20 centimeters higher than it is now.
B. The sea will be empty if we continue fishing at this pace.
C. The problems to explore the sea will have been largely solved.
D. People will depend largely on sea foods and minerals.

[单项选择]
What do the experts believe will happen by the year 2050
A. The sea level will be 20 centimeters higher than it is now.
B. The sea will be empty if we continue fishing at this pace.
C. The problems to explore the sea will have been largely solved.
D. People will depend largely on sea foods and minerals.

[填空题]Some experts believe that the reason why the Roman Catholic Church set the birth of Christ on December 25th is that that day was the New Year’ s Day for the ancient Romans.

[单项选择]Most experts believe that an ever-increasing number of countries and terrorist groups will gain the technical capability to acquire and use chemical and biological weapons. But use of these weapons by hostile states or terrorist groups is not inevitable. Even when locked in bloody conventional wars, nations that have considered using these weapons have generally been deterred by the risk that their opponents would retaliate in the same way or escalate the conflict elsewhere. Terrorist groups with the technical capacity to acquire and use a chemical or biological weapon have typically lacked an interest in doing so, while groups interested in such weapons have generally lacked the necessary technical skills.
Assessing future threats, however, involves more than simple extrapolation from past trends. In the case of chemical and biological weapons, it appears that the likelihood of use by both hostile states and terrorist groups is growing, and it is clear that even one such at- tack
A. They want to call more public attention.
B. They have the chemical and biological weapons.
C. They don’t want to loathed by the public.
D. They are Aum followers.

[单项选择]If the ivory trade continues, experts believe, the elephant will soon become extinct in Africa, because poaching is rife in many areas. A total ban on ivory trading would probably prevent the extinction. However, the country of Zimbabwe—which has virtually eliminated poaching within its borders and which relies on income from carefully culling elephant herds that threaten to become too big—objects to such a ban. Zimbabwe holds that the problem lies not with the ivory trade but with the conservation policies of other countries.
Which one of the following principles forms a logical basis for Zimbabwe’s objection to a ban
A. International measures to correct a problem should not adversely affect countries that are not responsible for the problem.
B. Freedom of trade is not a right but a consequence of agreements among nations.
C. Respecting a country’s sovereignty is more important than preventing the extinction of a species.
D. Prohibitions affecting several countries should be enforced by a supranational agency.
E. (E) Effective conservation cannot be achieved without eliminating poaching.

[填空题]Some experts believe that, if not for the cultural changes that Africa has experienced, the AIDS virus would not have spread to its present extent.

[简答题]By the year 2050, experts believe that the problems to explore the food, minerals and energy resources of the sea will have been largely solved.