line-to-line

例句：

1. 1. The soldiers lined up to salute the flag.
   士兵们排成一行向国旗致敬。
2. 2. She lined up her books on the shelf.
   她把书整齐地排列在书架上。
3. 3. The students lined up for the assembly.
   学生们排队参加集会。