fall astern的用法和样例：
例句
用作及物动词 (vt.)
- When the engine failed, we had to drop astern.
当发动机发生故障，我们不得不落在后面。 - Derek, who was close behind, saw the ticket fall and quickly picked it up.
德里克紧跟在后面，看见车票掉了并迅速捡起来。
词汇搭配
- fall astern 落在后面
