题目

完形填空 Lightning flashed through the darkness over Sibson's bedroom skylight（天窗）.Sibson was shaken by a clap of thunder 1 he knew what was happening. The storm had moved directly 2 his two-story wooden house. Then he heard the smoke alarm beeping. Sibson rushed down the stairs barefoot to 3 ; he opened the door to the basement（地下室）, and flames 4 out. Sibson ran back upstairs to call 911 from his bedroom. “I felt 5 because the room had a separate outdoor stairway,” he explains. But the phone didn't work, and when he tried to go down the outdoor stairway, he was 6 by如图，小明同学面对悬崖大叫一声，经过1s听到回声，小明与悬崖间的距离大约是 [     ]A.340 mB.170 mC.34mD.17m