Even a mighty express train can be held up by signals. But when the train dawdledat station after station, I began to wonder. It suddenly dawned on me that thisexpress was not roaring down the line at ninety miles an hour, but barely chuggingalong at thirty.

　　13.Even a mighty express train can be held up by signals.

　　因为即便是特别快车也可能被信号拦住。

　　语言点:句子结构分析:can be held up by signals是典型的被动语态的用法。

　　14.But when the train dawdled at station after station, I began to wonder.

　　但是，当火车一站接着一站往前蠕动时，我便产生了怀疑。

　　语言点1:dawdle一词在此的用法是夸张修辞格。

　　语言点2:station after station的意思是“一站又一站”。

　　15.But when the train dawdled at station after station, I began to wonder. It suddenlydawned on me that this express was not roaring down the line at ninety miles an hour,but barely chugging along at thirty.

　　我突然感到这趟快车并没以时速90英里的速度呼啸前进，而是卟哧卟哧地向前爬行，时速仅30英里。

　　语言点:句子结构分析:it指代火车开得慢的事实。Not…but…的意思是“不是…而是…”。