beginning-of-tape marker

例句：

1. 1.This tape has a beginning-of-tape marker on it.
   这个磁带上有一个磁带起始标记。
2. 2. The recording was made with a beginning-of-tape marker.
   录音是用一个磁带起始标记器录制的。
3. 3.The technician used a beginning-of-tape marker to mark the start of the recording.
   技术人员使用磁带起始标记器来标记录音的开始。