题目
Imagine you are Alice, stepping through the looking glass. Suddenly everything is re versed. Doorknobs are on the wrong side of doors. The gearshift in your car is in the wrong place. Twenty-five million Americans wake up every day in just such an awkward situation. They are the one in ten of us who are left-handed and must face the world designed for the right-handed majority. Why we are left-or-right-handed remains one of the great unsolved mysteries of science. We know that nearly two out of three lefties are male and that left-handedness runs in families. According to one study, almost half the offspring of two left-handed parents will be lefthanded. The Scots-Irish family Kerr (from the Gaelic word for "left")produced so many left-handers that in 1470 the family built its castle’s spiral stairways with a reverse twist to favor left-handed swordsmen. On the other hand, heredity alone cannot explain leffies. At least 84 percent of them are born of two right-handed parents. And in 12 percent of genetically identical twins, one will be right-handed, the other left. Perhaps the greatest puzzle of all is not why some people are left-handed, but rather why so few are. So, scientists are trying to discover the truth of the matter, and they are beginning to gain insight into many ways left-handed differ from right-handed by considering how their brains work.The reason why so few are left-handed （） A. has nothing to do with heredityB. remains one of the great unsolved mysteries of scienceC. has little to do with the working of their brainsD. is that left-handers are mainly twins
Imagine you are Alice, stepping through the looking glass. Suddenly everything is re versed. Doorknobs are on the wrong side of doors. The gearshift in your car is in the wrong place. Twenty-five million Americans wake up every day in just such an awkward situation. They are the one in ten of us who are left-handed and must face the world designed for the right-handed majority. Why we are left-or-right-handed remains one of the great unsolved mysteries of science. We know that nearly two out of three lefties are male and that left-handedness runs in families. According to one study, almost half the offspring of two left-handed parents will be lefthanded. The Scots-Irish family Kerr (from the Gaelic word for "left")produced so many left-handers that in 1470 the family built its castle’s spiral stairways with a reverse twist to favor left-handed swordsmen. On the other hand, heredity alone cannot explain leffies. At least 84 percent of them are born of two right-handed parents. And in 12 percent of genetically identical twins, one will be right-handed, the other left. Perhaps the greatest puzzle of all is not why some people are left-handed, but rather why so few are. So, scientists are trying to discover the truth of the matter, and they are beginning to gain insight into many ways left-handed differ from right-handed by considering how their brains work.The reason why so few are left-handed （）
- A. has nothing to do with heredity
- B. remains one of the great unsolved mysteries of science
- C. has little to do with the working of their brains
- D. is that left-handers are mainly twins
题目解答
答案
B
解析
考查要点：本题考查对文章主旨的理解，特别是对关键细节的捕捉能力。需要结合上下文，准确判断选项中哪一项与原文信息完全一致。
解题核心思路：文章最后一段明确指出“为什么左撇子如此之少”是科学界尚未解决的最大谜团之一。破题关键在于抓住原文中的核心表述“the greatest puzzle of all is not why some people are left-handed, but rather why so few are”，并对应选项中的直接引用。
选项分析：
- 选项B：“remains one of the great unsolved mysteries of science”直接对应原文最后一段首句“Why we are left-or-right-handed remains one of the great unsolved mysteries of science”，且最后一段进一步强调“why so few are left-handed”是“the greatest puzzle”，因此正确。
- 选项A错误：文章提到遗传有一定影响（如“left-handedness runs in families”），但明确说明“heredity alone cannot explain lefties”，因此排除。
- 选项C错误：文章确实提到“considering how their brains work”，但未将“few left-handed”归因于大脑工作方式，而是强调这是未解之谜。
- 选项D错误：文中未提及左撇子与双胞胎的关联，仅提到12%同卵双胞胎中一人左撇子，但这属于遗传差异现象，非原因。