[音频]Subsequently, William Wyler chose her to be the lead in Roman Holiday, _________ Gregory Peck. For her role as Princess Ann, she won the 1953 Academy Award for Best Actress and began a string of box office hits.Audrey Hepburn became a goodwill ambassador and spokesperson for UNICEF in 1986. Traveling to areas ___________ famine and devastation, Hepburn worked to raise public __________ of the plight (困境) faced by children in times of crises.
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[音频]Her commitment to improve the welfare of children across the world was intense and genuine. This commitment earned her the Presidential Medal of Freedom and the ____________ Award from the Congress on Racial Equality. Soon after her trip to Somalia in 1991, Hepburn __________________ colon cancer. In 1993, Audrey Hepburn died at the age of 63.
金属铯的红限波长λ0= 660nm,其逸出功A为()。
A. 1.88 eV
B. 2.0 eV
C. 3.2 eV
D. 1.22 eV
要使金属发生光电效应,则应该()
A. 只要尽可能增大入射光的强度
B. 选用波长较红限波长更短的光波为入射光波
C. 选用波长较红限波长更长的光波为入射光波
D. 增加光照的时间
下列各物体,哪个是绝对黑体?()。
A. 不辐射可见光的物体
B. 不辐射任何光线的物体
C. 不能反射可见光的物体
D. 不能反射任何电磁波的物体