1 . On the morning of September 11,2001, computer sales manager Michael Hingson, who is blind, went early to his office on the 78th floor of the North Tower of the World Trade Center to prepare for a meeting. As Michael worked, his guide dog, a Labrador retriever     1     (name) Roselle, dozed by his feet.

At 8:46 a.m., a tremendous boom rocked the building, eliciting screams throughout the floor. Michael grabbed Roselle, trusting that the dog     2     (lead) him out of the danger, and they navigated their way to a stairwell.

“Forward,” Michael instructed, and they descended the first of 1,463 steps to the lobby.     3     about ten floors, the stairwell grew crowded and hot, and the fumes from jet fuel had made it hard to breathe.

When a woman became crazy, yelling that they wouldn’t make it. Roselle accompanied the woman     4     she finally petted the dog, calmed herself, and kept walking down the stairs.

Around the 30th floor, firefighters started passing Michael on their way up. Each one stopped to offer him assistance. He declined but let Roselle be petted,     5     (provide) many of the firefighters with     6     would be their last experience of unconditional love.

After about 45 minutes, Michael and Roselle reached     7     looby, and 15 minutes later, they emerged outside to a scene of chaos. Suddenly the police yelled for everyone to run as the South Tower began to collapse.

Michael kept a tight grip on Roselle’s harness, using voice and hand commands, as they ran to a street opposite the crumbling tower. The street bounced like a trampoline, and “a deafening roar” like a hellish freight train filled the air. Hours later, Michael and Roselle made it home safely. At that moment, they thought they were     8     (lucky ) in the world.

In the months that followed, Michael became a spokesperson for Guide Dogs for the Blind, the organization by which Roselle     9     (train). Together, they spread their message about trust and teamwork.

In 2004, Roselle developed a blood disorder,     10     prevented her from guiding and touring. She died in 2011.

“I’ve had many other dogs,” Michael wrote, “but there is only one Roselle.”