问题
选择题
________on a clear day，far from the city crowds，the mountains give him a sense of peace.
A．Walked
B．To walk
C．Having walked
D．When he is walking
答案
答案：D
答案 D [考查非谓语动词和状语从句。A、B、C三项均与主语“the mountains”不一致，故排除非谓语动词用法。D项为时间状语从句。]