完形填空。阅读下面短文，掌握其大意，然后从1~15各题所给的A、B、C和D项中，选出最佳选项。
When she looked ahead, Florence Chadwick saw nothing but a solid wall of fog, Her body was 1 . She had been swimming for nearly sixteen hours.
Already she was the first woman to 2 the English Channel in both directions. Now, at age 34, her 3 was to become the first woman to swim from Catalina Island to the California coast.
On the July Fourth morning in 1952, the sea was icy and the fog was so heavy that she could 4 see her support boats. Sharks swam toward her lone figure, only to he 5 away by gun shots. Against the cold sea water, she struggled on -- hour after hour -- while millions watched on national 6 .
