单选题 Recent studies of the human brain have resulted in some interesting discoveries. Scientists believe that a way to improve the power of the brain may soon be possible.
Scientists have discovered that the brain can make its own drugs. The brain 1 a protein substance which can act directly 2 the brain to change aspects of mental activity. Some may change or improve, for example, creativity, intelligence, imagination, and good 3 .
Chemicals found in the brain 4 messages. In recent years scientists have found chemicals that 5 mood, memory and other happenings of the mind. About 25 have been found 6 .
Today the role of chemicals and the protein substance in human behavior is creating much interest. Research seems to show that they may help 7 insomnia, pain, and mental illness. They have a great 8 to stimulate the brain to 9 deficiencies. They also improve the qualities of memory and learning already in the brain. They 10 the secret on mood and emotion. Some day there may be a chemical way to create a better and more efficient brain.
【正确答案】 D
【答案解析】[解析] entertain娱乐，招待；restrain抑制，制止；sustain撑住，维持；contain包含，容纳。根据上下文，此处应该是“大脑含有一种蛋白质……”。
【正确答案】 B
【答案解析】[解析] act on固定搭配，表示“对……起作用”。
【正确答案】 D
【答案解析】[解析] 本句的Some指代的是前一句的aspects of mental activity。选项中符合大脑活动的只有记忆memory。
【正确答案】 C
【答案解析】[解析] 本句的意思是“大脑中的化学物质携带信息”。因此选carry，意为“携带”。
【正确答案】 B
【答案解析】[解析] 本句的意思是“近年来科学家发现了可以影响情绪、记忆和其他大脑内发生的事的化学物质”。
【正确答案】 C
【答案解析】[解析] 本句的意思是“迄今为止发现了大约25种化学物质”。
【正确答案】 D
【答案解析】[解析] 本句的意思是“研究似乎表明它们有助于控制失眠、疼痛和精神疾病”。
【正确答案】 B
【答案解析】[解析] 本句的意思是“它们有一种巨大的能力可以刺激大脑克服缺陷。”
【正确答案】 C
【答案解析】[解析] 参见上一小题解释，有“克服”之意的只有选项C。
【正确答案】 B
【答案解析】[解析] 根据上一句，这里的时态应该用一般现在时。