夏令时标准答案: 4 I$ y2 n- U. N8 D% S: b8 }* @ 0 p' G. U9 z, M4 hDaylight Saving Time begins for most of the United States at 2 a.m. on the first Sunday of April. Time reverts to standard time at 2 a.m. on the last Sunday of October. 0 M5 ~) y/ ? M5 S( N" j2 m4 \