growl、bark、howl与roar这些动词均含狗等的“吠、叫”之意。
growl : 指被激怒的狗发出低长的咆哮声，以示威胁。用于人时，指咆哮着喊叫，怒冲冲地发牢骚。
- The dog growled at her and snapped at her ankles.
那条狗咆哮着在她脚踝上咬了一口。 - "Not now, I'm busy," he growled.
“现在不行，我忙着呢，”他吼道。
bark : 指发出刺耳的汪汪声，系典型的狗吠。
- The sergeant barked (out) a succession of orders to the new recruits.
中士向那些新兵大声下了一连串命令。
howl : 指声音响亮，拖得很长，如哀愁的哭声。用于人时，指通常因痛苦、悲伤或其他强烈情感而“号叫、哀号”。
- In the silence of the night, a lone wolf howled.
在寂静的夜里，一只孤独的狼在嚎叫。 - An injured dog lay in the middle of the road, howling with/in pain.
一只受伤的狗躺在路中间，痛苦地嚎叫着。 - We were howling with laughter.
我们放声大笑。
roar : 指狮子的吼叫。
- We could hear the lions roaring at the other end of the zoo.
我们可以听到狮子在动物园的另一端咆哮。
