[单项选择]In January 2002, during the first weeks of a six-month stay at the Children’s Hospital of Philadelphia for leukemia (白血病) treatment, Michael wandered over to his hospital window in search of relaxation. The (36) first-grade Watched a construction crew (37) on a 10-story addition to the hospital. (38) Michael’s third-floor window, Ritchie, an iron-worker from the East Falls section of Philadelphia, (39) and saw "this kid with no hair (40) face was pressed up to the window. I waved, and he smiled and (41) . I’ll never forget that," says Ritchie, a father of three.
As winter (42) spring, Michael watched, fascinated (着迷), as 3 000 tons of steel (43) formed the skeleton of the building. One day he colored a message for the crew and held (44) up to the window: Hi, Local Iron Workers. I’m Mike. Ritchie and the (45) crew messaged back: Over the (46) months, as his treatment continued, Ritchie and the crew (47)
A. Before
B. Since
C. While
D. When