Hxen.com's tips：Every day persisted can learn English well!-->■Learn English Everyday■
In Washington D.C., U.S. President Barack Obama and first lady Michelle Obama on Tuesday observed a moment of silence on the south lawn of the White House before heading for the Pentagon where another memorial ceremony was organized, with attendance of service members, along with families of the 184 people who died when the Pentagon was hit by the hijacked American Airlines jetliner 11 years ago.
"This is never an easy day, but it is especially difficult for all of you, the families of nearly 3,000 innocents who lost their lives," said Obama, adding that the nation has always mourned with the families of victims together to remember their loved ones.
Obama also stressed that the country is safer now as "al Qaeda' s leadership has been devastated and Osama bin Laden will never threaten us again."
"Eleven years ago, memorial services were held for Americans of different races and creeds, backgrounds and beliefs. And yet, instead of turning us against each other, tragedy has brought us together. I've always said that our fight is with al Qaeda and its affiliates, not with Islam or any other religion."
At the same function, U.S. Secretary of Defense Leon E. Panetta echoed Obama by saying although al-Qaeda remains a threat, the U.S. has made it difficult to plan and conduct another 9/11 attack.
"And we will continue to fight them in Yemen, in Somalia, in North Africa," said Panetta.
U.S. Vice President Joe Biden on Tuesday also participated in a wreath-laying at a memorial function held in Shanksville, Pennsylvania, where 40 passengers aboard United Flight 93 were killed when that plane crashed as they fought back against their hijackers.