In cumulus convection ascent rates of several metres a second give a cooling rate of a few degrees per minute . 在积云中，每秒几米的对流上升速度造成的冷却速率为每分钟几度。
Television systems, which transmit 30 picture frames per second, must operate on a broad electromagnetic spectrum . 每秒传输30幅图象画面的电视系统，它必须工作于宽带电磁波谱。
It is inconceivable that so strong a source of energy can be switched on and off in as little time as 1/30 second . 真难以想象如此强的能源可在130秒这样短的时间内关闭和开启。
An automobile is driven along a highway which is characterized by alternating speed zones of 15m/s and30m/s . 一汽车沿高速公路行驶。这公路交替地标出15米秒与30米秒的限速地段。
There is an onset of high frequency motion which is common to both components about 1. 8 sec. after the beginning of the record . 大约在记录开始18秒后，两种分量都有高频运动出现。
For low-frequency currents(up to about 15, 000 cycles per second)an iron core, called a magnetic circuit; is placed . 对于低频率电流（约15，000周秒以内），置有一个叫作磁路的铁心。
It was fifteen to twenty seconds before the whole of the working area of the ship was filled with black acrid pungent smoke . 十五秒到二十秒钟后，舰上整个工作区域到处都是刺鼻的黑色浓烟。
