Surrounded by celebrity¹ performers and characters from the North Pole, the Obama family on Thursday led a countdown and lighted the National Christmas Tree.

本周四，奥巴马一家在著名艺人和北极来客的陪同下，一起喊着倒计时，点亮了“国家圣诞树”。

President Barack Obama, first lady Michelle Obama and daughters Sasha and Malia help to light the National Christmas Tree, Thursday, Dec. 3, 2009, in Washington.

First lady Michelle Obama and daughters Malia and Sasha helped President Barack Obama press a button to light the tree, an annual tradition since the 1920s. "I'm technologically² challenged and I might not get this right," the president joked. "Everybody has got to help me out（帮帮我） here."

The Obamas and the spectators counted down from five, and the red and yellow lights came alive on the 40-foot Colorado blue spruce（蓝叶云杉） growing on the Ellipse, just south of the White House. "It worked," Obama shouted.

Performers including singer Sheryl Crow, hip³ hop⁴ artist Common and "American Idol⁵" winner Jordin Sparks dazzled（目眩的） the crowd, bundled in coats and scarves（围巾）.

"I told Sasha we're not on 'American Idol,'" the president said at one point. The Obama family and Vice⁶ President Joe Biden and his grandchildren watched from seats beside the stage, behind a clear protective shielding（防护屏）.

The characters Santa Claus and Mrs. Claus also joined the celebration, saying it was their "date night."

"You know what I'm talking about," Mrs. Claus told the Obamas, referring to the couple's nights out on the town together. The president later met Santa Claus on stage and briefly⁷ danced with him.

Before the tree was lit, Obama said its story might be Christian⁸ but its lesson is universal.

"It represents a tradition that we celebrate as a country — a tradition that has come to represent more than any one holiday or religion, but a season of brotherhood⁹ and generosity¹⁰ to our fellow citizens," he said.

He said it's important to remember those who have lost their jobs and homes in this season as well as military service members and their families who are apart during the holidays. "We will be thinking of you and praying for you during this holiday season," he said.

Every president has presided over（主持） the tree lighting¹¹ since Calvin Coolidge in 1923. The current National Christmas Tree was planted on the Ellipse in 1978.