A. The world is shrinking physically. B. The 20th century saw incredible inventions.. C. The way we live and communicate has changed over the centuries. D. The computer revolution has made life more convenient. 参考答案:C 答案解析:本题测试对全文主要内容的理解和概括能力。根据文中的第二句可直接排除选项A,选项B和D都只是全文的一部分内容。由于原文讲述了不同历史阶段的发明及对人们生活和交流的影响,因此选项C最符合原文大意。