日期：
来源：雅诚德英语网
The start and stop observation points are marked to show when the timestamps are recorded.
开始和停止观察点已标记出来，以显示记录时间戳的时间。
The start and stop observation points are marked to show when the timestamps are recorded.
开始和停止观察点已标记出来，以显示记录时间戳的时间。