He came to Washington's George Washington University hospital to 2)donate blood. But only two of the 3)victims from the Pentagon explosion were being treated there, and hospital officials thanked the 4)prominent historian and told him the donation would not be needed at this time.

Speaking to VOA outside the hospital, Mr. McCullough compared the 5)tragedy to the Japanese attack on the U.S. 6)naval base at Pearl Harbor in Hawaii in 1941.

"To me, it is, perhaps, worse even than Pearl Harbor because at Pearl Harbor they attacked a military target," he said. " This comes out of the blue on a perfectly gorgeous summer morning, coordinated, planned, vicious ... madness."

The 69-year-old historian says that Tuesday's attacks were far worse than the bombing of the federal building in Oklahoma City in 1995, which was carried out by 7)domestic terrorists. He says one of the things that must be avoided at all costs is a reaction to these acts of terrorism that changes the very nature of the democratic system established by the founding fathers.

"Let us hope that the open society can continue. We are tough. We are 8)resilient. We will come back. We will clean it up. We will build again. We will go to work. What we have as an open society is very valuable," Mr. McCullough said. "It is 9)essential. It is all the more reason to understand how we got to where we are and what other 10)sacrifices were made to maintain an open society."

Mr. McCullough also cautions against reacting with blame against the law enforcement and intelligence community. He says these are the people who are trying to protect us and they are not to blame.

David McCullough is a Pulitzer Prize winning author who has written about various people and achievements in American history. His latest book is a biography of founding father John Adams.

(1) provide[prE5vaId]v.供应, 供给, 准备, 预防, 规定

(2) donate[dEJ5neIt]v.捐赠, 赠予

(3) victim[5vIktIm]n.受害人, 牺牲者, 牺牲品

(4) prominent[5prRmInEnt]adj.卓越的, 显著的, 突出的

(5) tragedy[5trAdVIdI]n.悲剧, 惨案, 悲惨, 灾难

(6) naval[5neIv(E)l]adj.海军的

(7) domestic[dE5mestIk]adj.家庭的, 国内的

(8) resilient[rI5zIlIEnt]adj.弹回的, 有回弹力的

(9) essential[I5senF(E)l]adj.本质的, 实质的, 基本的n.本质, 实质, 要素

(10) sacrifice[5sAkrIfaIs]n. v.牺牲, 献身, 祭品, 供奉