1.boom是象声动词,基本意思是“隆隆作响”,常用于其引申意“繁荣”“激增”“迅速发展”。
2.boom是不及物动词,其现在分词booming在句中常用作伴随状语。

boom out(v.+adv.)
▲boom sth ⇔ out
1.低沉的发出 give forth with a booming sound
The clock booms out nine.钟隆隆地敲了九下。
The big man's voice boomed out above the rest.这位大汉低沉的声音压过了其他人。
2.用低沉的声音说话 utter in a deep voice
He boomed out his answer.他用低沉的声音回答。
He boomed out Shakespearian verses.他用低沉的声音读出莎士比亚的诗句。

用作不及物动词
▲S+～(+A)
The thunder boomed like a cannon.雷声隆隆,像大炮一样。
The guns boomed.枪声轰轰。
Business is booming.商业日趋繁荣。
He is booming as a teacher.作为一位教师,他日趋成功。
The economy is beginning to boom in China.中国经济将开始迅速发展。

The new aircraft creates a sonic boom.那种新飞机会产生声震。
The big tax cuts fueled a consumer boom.税额的大削减刺激了消费的迅速增长。

［同义词］ n. blast, flourish
［反义词］ n. depression