drone的第三人稱單數形式

　　例句：

　　A plane was droning in the distance.

　　飛機在遠處嗡嗡地響。

　　The drone of the engine made her sleepy.

　　發(fā)動機的嗡嗡聲使她困倦。

　　Outside the tent I could hear the constant drone of flies.

　　我能夠聽到帳篷外面蒼蠅不斷的嗡嗡聲。