论文部分内容阅读
(A)难易度:☆☆☆In 1989 an 8.2 earthquake almost flattened America, killing over 30,000 people in less than four minutes. In the middle of
(A) Difficulties: ☆☆☆In 1989 an 8.2 earthquake almost flattened America, killing over 30,000 people in less than four minutes. In the middle of