This produces a waveform of one polarity operating at a frequency twice that of the mains supply.

经过整流后得到的是一个频率为交流电源两倍的单极波形。

Always make sure that the shredder has been disconnected from the mains supply before you disassemble it.

务必让该碎纸机已被断开的电源，然后再拆卸它。

Most Nigerians have no more than a few hours of mains supply a day—the economy's single biggest bottleneck.

大多数的尼日尼亚人每日的水电供应不超过数小时。这成为了国家经济的最大瓶颈。

Heat meters designed to operate from an ac mains supply shall be wired in accordance with wiring regulations applicable.

温度传感器由AC交流电源供应，配备的电线符合电线规章。

Flexibility and reduced stock holdings cause problems when different mains supply plugs are required for different markets.

当不同的市场需要不同的主控电源插座的时候，灵活性和减少存货两者之间可能会出现矛盾。