教学目标:
语法：past tense time expressions
词汇：interview, interviewer, event, exhausted, downtown, vacuum, rail, ceremony, track, Los Angeles, California, sick,
短语：at a speed of, per hour, high-speed,
Ⅱ重难点突破:
1. 语法(Past tense time expressions)
① 一般过去时表示过去某时发生的动作或情况，在用以下短语或副词时常用此时态。
just now, at that time, last night, a week ago, in the old days,
the other day, then, during his middle school years
② 有些情况尽管没用上述时间状语，但实际上是过去发生的情况，也用一般过去时。
