【正确答案】 D

【答案解析】[听力原文]

Anatomy: The Brain

Professor: I"ve brought in a picture of the human brain today, which we are going to look at and discuss in detail. The parts of the brain that we are going to talk about today are dearly labeled. The brain is like our command center for all our daily functions and allows us to cope with our environment. How we communicate with words, actions, thoughts, and feelings axe all centered in the brain. Some researchers believe that the brain is so complex and mysterious that we will never be able to fully understand it. Some have even referred to it as a little black box like those found on a plane that contain all the critical and highly confidential information of the flight. That being said, there are parts of the brain that we do know about, like the parts listed on the diagram, and we also know their functions that each bring to make our body work. It"s easiest to think of the brain as three connected parts: the cerebrum, brainstem, and cerebellum.
Let"s start off with the brainstem, which is found at the bottom of the brain and joins the cerebrum to the spinal cord. The brainstem has an important role because it controls lots of critical functions including respiration, regulation of the heart rhythms, basic aspects of sound localization, which allows us to identify the origin of a detected sound, and reflexes. As you can see on the diagram, the brainstem includes the midbrain, the pons, and the medulla. These allow functions such as the movement of our eyes and mouth, passing on sensory messages like hot, pain, loud, and other functions such as hunger, consciousness, body temperature, sneezing, coughing, vomiting, and swallowing. Next, we"ll look at the second largest part of the brain--the cerebellum. It is located at the lower back of the head and is attached to the brainstem. It is made up of two hemispheres and its functions are to control complex voluntary motor functions such as walking, balance and posture. The third and largest part of our brain is the cerebrum. Its associations are conscious thought, movement and sensations such as touch, vision, hearing, judgment, reasoning, problem solving, and emotions. It is made up of two halves with each half controlling the opposite side of the body. The corpus callosum connects the two halves, and delivers messages between them. There are four lobes that make up the cerebrum, the frontal, temporal, parietal, and occipital. The frontal lobe is located in the front of the head and is involved in personality, characteristics and movement. The parietal lobe is in the middle part of the brain, and helps you to identify objects and understand spatial relationships like where your body is compared to objects around you. It also helps make meaning of pain and touch in the body. The occipital lobe allows you to see and is located at the back of the brain. Finally, the temporal lobe assists with memory, speech, and sense of smell and is found at the sides of the brain. The average weight of the adult human brain is anywhere between 1 and 1.5 kilograms. Some people say that we only use 10% of our brain, but this is just a myth. In fact, we use our entire brain. That being said, we can claim that most people only use a very small fraction of the cognitive potential of their brain. Different cultures have used several methods to improve their cognitive potential such as reading, education, puzzle solving and critical thinking. I hope this brief introduction to the brain helps you understand the brain and its different functions.

[解析] 教授在讲座中明确指出大脑由三个部分(three connected parts)构成，即the cerebrum，brainstem，and cerebellum。应选择D选项。