A few days later during a speech in Prague April 5, Mr.Obama said his administration will take concrete steps toward a world without nuclear weapons.

VOA: standard.2009.04.08

That sign languages may be full-blown languages but they just take--they're just harder to learn because the brain and the body have adapted for speech.

手语或许是成熟的语言,但它们更难学,因为大脑和身体已经适应了口语

耶鲁公开课 - 心理学导论课程节选

Mr.Obama's June 4 speech in the Egyptian capital will take place as part of a trip that will include visits to Germany and France to commemorate the 65th anniversary of D-Day, when Allied forces stormed the beaches of Normandy during World War Two.

VOA: standard.2009.05.09