内蒙古通辽市科尔沁左翼中旗实验高级中学2022-2023学年高二下学期期中考试英语试题

2022-2023学年度下学期高二年组 期中考试（英语）试卷 测试时间：120分 总分：150分 注意事项： 1. 答题前，考生先将自己的姓名、准考证号填写清楚。 2. 请按照题号顺序在答题卡各题目的答题区域内作答，在试卷上答题无效。 第二部分 阅读理解（共两节，满分40分） 第一节 （共15小题；每小题2分，满分30分） 阅读下列短文，从每题所给的A、B、C和D四个选项中，选出最佳选项。 A It is believed that human story begins in Africa and ends about 200，000 years later with their seven billion descendants (后代) spread across the Earth, living in peace or at war, their faces lit by campfires and computer screens. In between is an exciting tale of survival, movement, isolation, and conquest, most of it occurring before recorded history. Who were those first modern people in Africa? What routes did they take when they left their home continent 60，000 years ago to expand into Europe and Asia? When and how did humans reach the Americas? For decades, the only proof was found in a small number of scattered bones and artifacts that our ancestors left behind on their journeys. In the past 20 years, however, DNA technologies have allowed scientists to find a record of ancient human migrations in the DNA of living people. “Every drop of human blood contains a history book written in the language of our genes，” says population geneticist Spencer Wells. The human genetic code, or genome, is 99.9 percent identical throughout the world. But while the bulk of our DNA is the same, what's left is responsible for our individual differences—in eye color or disease risk, for example. On very rare occasions, a small change, called a mutation, can occur, which is then passed down to all of that person's descendants. Generations later, finding that same mutation in two people's DNA indicates that they share the same ancestor. By comparing mutations in many different populations, scientists can trace their ancestral connections. These ancient mutations are easiest to track in two places: in DNA that is passed from mother to child (called mitochondrial DNA, or mtDNA for short), and in DNA that travels from father to son (known as the Y chromosome, th