复数： secs
易混淆的单词： SecSEC

I have used nd filter and exposure was 47 sec .

于是我用nd镜和曝光47秒拍摄了这张照片

4 Sec backup pumps within the secondary loop automatically turn on .

4秒二次回路中的备用水泵自动启动。

0 Sec the pumps in the secondary loop shut down automatically , due to a slight malfunction .

0秒二次回路中的水泵因为一个小故障而自动关闭。

4 Min 30 sec operators observe that the water level in the primary system is rising and that the pressure is decreasing .

4分30秒操作员观察到主回路的水位在上升且压力在下降。

3 Sec the porv ( pressure relief valve ) opens automatically , releasing steam into a holding tank .

3秒减压阀自动打开，将蒸汽释入一个储存罐。