line at a time

例句：

1. 1. The line ofcars was long and slow.
   汽车排成了长队，缓慢前行。
2. 2. Theline of soldiers marchedin unison.
   士兵们整齐地列队前进。
3. 3. The line of peoplewaiting for the bus stretched out into thedistance.
   等待公交车的人群排成了一条长龙。