As work becomes more engrossing and narrowing the need is more urgent for recognized and carefully guarded periods of leisure.
随着工作变得越来越引人入胜， 缩小了对公认和精心保护的闲暇时间的需求变得更加紧迫。
英语百科
Guard interval
（重定向自Guard period）
In telecommunications, guard intervals are used to ensure that distinct transmissions do not interfere with one another. These transmissions may belong to different users (as in TDMA) or to the same user (as in OFDM).
The purpose of the guard interval is to introduce immunity to propagation delays, echoes and reflections, to which digital data is normally very sensitive.