[单项选择]

Earth’s Inner Core

 

Scientists have long struggled to understand what lies at the planet’s center. Direct observation of its center is impossible, so researchers must (1) to other evidence.
In 1889, a German scientist detected a severe earthquake in Japan. Geophysicists concluded that shock waves (2) jolts (晃动) from one side of Earth through the center to the other side. Then in 1936, Danish geophysicist Inge Lehmann studied the waves’ (3) to determine that within Earth’s core of molten (溶化了的) iron lies a solid inner core—but (4) that core was made of eluded (难倒) her. Other geophysicists quickly determined that Lehmann’s inner core was composed mostly (5) iron. Since then, Lehmann’s discovery has (6) conventional Earth science.
But now scientists are challenging traditional theory with new and radical (
A. after
B. before
C. since
D. when

Scientists have long struggled to understand what lies at the planet’s center. Direct observation of its center is impossible, so researchers must (1) to other evidence.
In 1889, a German scientist detected a severe earthquake in Japan. Geophysicists concluded that shock waves (2) jolts (晃动) from one side of Earth through the center to the other side. Then in 1936, Danish geophysicist Inge Lehmann studied the waves’ (3) to determine that within Earth’s core of molten (溶化了的) iron lies a solid inner core—but (4) that core was made of eluded (难倒) her. Other geophysicists quickly determined that Lehmann’s inner core was composed mostly (5) iron. Since then, Lehmann’s discovery has (6) conventional Earth science.
But now scientists are challenging traditional theory with new and radi
A. create
B. receive
C. feel
D. overcome

Scientists have long struggled to understand what lies at the planet’s center. Direct observation of its center is impossible, so researchers must (1) to other evidence.
In 1889, a German scientist detected a severe earthquake in Japan. Geophysicists concluded that shock waves (2) jolts (晃动) from one side of Earth through the center to the other side. Then in 1936, Danish geophysicist Inge Lehmann studied the waves’ (3) to determine that within Earth’s core of molten (溶化了的) iron lies a solid inner core—but (4) that core was made of eluded (难倒) her. Other geophysicists quickly determined that Lehmann’s inner core was composed mostly (5) iron. Since then, Lehmann’s discovery has (6) conventional Earth science.
But now scientists are challenging traditional theory with new and radical (7) . F
A. try
B. leave
C. turn
D. point

 Scientists are now studying a new field of research called psychoimmunology. It is based on the idea that people who are depressed or have a lot of stress are more likely to become sick. Researchers have recently found a connection between diseases and stressful situations. To test this theory, psychoimmunologists are trying to find a link between the brain and the immune system. The immune system in our bodies fights the bacteria and viruses which cause disease. Therefore, whether or not we are likely to get various diseases depends on how well our immune system works. Biologists used to think that the immune system was a separate, independent part of our bodies. Recently, however, they have found that our brain can affect our immune system. This discovery indicates that there may be a connection between emotional factors, such as stress or depression, and illness. Although many doctors in the past suspected a connection between emotional factors and disease, they had no p