夜幕完全笼罩山体时，我已然行在坡度有七八十度的千尺栋区域，此时就要手脚并用了。
B-Time I-Time I-Time I-Time I-Time I-Time I-Time I-Time I-Time O B-Person O O O O O O O B-Metric I-Metric I-Metric I-Metric O B-Location I-Location I-Location I-Location I-Location O B-Time I-Time O O B-Thing I-Thing O O O O