一 单项选择（共20小题，每小题0.5分，满分10分）
从A、B、C、D四个选项中，选出可以填入空白处的最佳选项。
1. On April 13th, 2012________ press conference is held by Los Angeles Police
Department at___________crime scene of a shooting incident.
A. a; the B. a; a C. the; a D. the; the
2. When ___ comes to saving energy , big changes start with small steps , like turning off the lights.
A. that B. this C. it D. one
3. I went to bed very late last night, ___, early the next morning .
A. or rather B. at least C. at most D. in a word
