完形填空
She died at the age of 15 in one of the history's greatest sad stories,1her thoughts live on to this day through the diary in which she recorded her2.Though she was touched by despair（绝望）and terror, the message of3in her words has encouraged many. Anne Frank, the most famous4child of World WarⅡ, is indeed a symbol of the Holocaust（大屠杀）.Her secret writings, which later came out5“The Diary of Anne Frank”,6of two years in the life of a young Jewish girl hiding in Nazi-controlled Amsterdam. To mark the 75th anniversary of her7,on June 12 this year(2004),www.annefrank.org is to8some rare photographs of the girl taken when she was 12.
Born in 1929,Anne Frank was a German-Jewish teenager who was9to go into hiding to10being arrested（逮捕）by the Nazis. She and her family, along with four 11,spent 25 months in a few small rooms above her father's office in Amsterdam. The family was12founded by the Nazis, and forced to go to a concentration camps（集中营）.In March 1945,nine months after she was arrested and shortly13the camp was liberated（解放）,Anne Frank was killed.
Her diary, first coming out in 1947, has become one of the world's most 14read books. It has been translated into 67 languages. The following is the most 15part of Anne's diary.
“It's16for me to build my enjoyable life on a foundation of chaos（混乱）,suffering and death. I see the world being slowly changed into a wilderness.I17the approaching thunder that, one day, will kill us too.I feel the18of millions.And yet,when I look up at the sky,I feel that everything will change for the19,that this cruelty shall end and that peace will20once more.”
—July 15, 1944
的圆心在双曲线
的右焦点且与此双曲线的渐近线相切，若圆
截得的弦长等于
，则
的值为（ ）