第34题: [单项选择]Arctic explorers may catch colds when ______. A. they are working in the isolated arctic regions B. they are writing reports in terribly cold weather C. they. are free from work in the isolated arctic regions D. they are coming into touch again with the outside world 参考答案:D 答案解析:[解析] 从第二段最后一句话得知,北极探险者可能患上风寒,是因为他们在接收包裹和邮件过程又接触了外界感染者。