boom out
v. 发生低沉的声音
例句与用法：
Our teacher boomed out his answer.
我们的老师用低沉的声音作出回答。
The clock began to boom out twelve.
时钟开始敲十二点。
词形变化：
动词过去式: boomed | 动词过去分词: boomed | 动词现在分词: booming | 动词第三人称单数: booms |
