如图，正方形ABCD中，E为AB的中点，AF⊥DE于点O，则$\frac{AO}{DO}$等于（　　）

桃花源记

       晋太元中，武陵人捕鱼为业。缘溪行，忘路之远近。忽逢桃花林，夹岸数百步，中无杂树，芳草鲜美，落英缤纷。渔人甚异之。复前行，欲穷其林。

       林尽水源，便得一山，山有小口，仿佛若有光。便舍船，从口入。初极狭，才通人。复行数十步，豁然开朗。土地平旷，屋舍俨然，有良田美池桑竹之属。阡陌交通，鸡犬相闻。其中往来种作，男女衣着，悉如外人。黄发垂髫，并怡然自乐。

       见渔人，乃大惊，问所从来。具答之。便要还家，设酒杀鸡作食。村中闻有此人，咸来问讯。自云先世避秦时乱，率妻子邑人来此绝境，不复出焉，遂与外人间隔。问今是何世，乃不知有汉，无论魏晋。此人一一为具言所闻，皆叹惋。余人各复延至其家，皆出酒食。停数日，辞去。此中人语云：“不足为外人道也。”

       既出，得其船，便扶向路，处处志之。及郡下，诣太守，说如此。太守即遣人随其往，寻向所志，遂迷，不复得路。

       南阳刘子骥，高尚士也，闻之，欣然规往。未果，寻病终。后遂无问津者。

    The Van Gogh Museum in Amsterdam has welcomed home two paintings by the Dutch master, more than 14 years after they were ripped (抢) off the museum's wall in a nighttime theft. Museum director Axel Rueger called their return “one of the most special days in the history of the museum.”

    The paintings were discovered last year by Italian police while they were searching suspected Italian criminals' farmhouse near Naples for evidence of drug dealing. The two paintings were wrapped in cotton sheets. They were stuffed in a box and hidden behind a wall in a toilet when they were found.

    The paintings were considered among the artworks most searched for in the world. After years in darkness, they can now shine again. They are back on display at the museum before being taken to the conservation studio for repair. Fortunately, they suffered remarkably little damage as thieves who had climbed up a ladder and broken a window to get into the museum in 2004 rip them out of their frames.

    “It is not only a surprise that the works have been recovered but it's even more surprising they are in relatively unharmed condition,” Rueger said.

    The museum director was on vacation when the call came last year from Italian authorities who believed they had recovered the paintings. He didn't celebrate right away. He'd had calls like this before.

    “I was hopeful but also a little hesitant. Over these years, we had so many occasions when people phoned us, contacted us, claiming that they knew something about the whereabouts (下落) of the works and each time it was false, the trace went cold,” he said. “So...the way has been till of disappointment.” But museum experts sent to Italy to check the authenticity(真实性) of the works quickly turned Rueger's doubts into delight.

    Rueger said the paintings are now back permanently at the museum, which is home to dozens of works by Van Gogh. “I'm very confident that everything is safe in the museum from now on,” he said.