例句與造句

1. Have heard strange humming or pulsing sounds , and you could not identify the source
   聽(tīng)到不能夠識(shí)別來(lái)源的奇怪的嗡嗡聲或脈沖式的聲音
2. It's difficult to find pulsed sound in a sentence. 用pulsed sound造句挺難的