"they manifested all the busyness of a pack of beavers"
"there is a constant hum of military preparation"
"the hum of distant traffic"
"She hummed a melody"
"This office is buzzing with activity"
"The refrigerator is humming"
The machine hummed all around us in the factory.
工厂里机器在我们周围嗡嗡作响。
The bees were humming around the hive.
蜜蜂在蜂箱周围嗡嗡地叫。
He was humming a tune to himself.
他轻声哼着一支曲子。
He hummed the tune to me.
他给我哼唱了这支曲子。