他加入了消防大队。
tā jiārù le xiāofángdàduì 。
He joined the fire brigade.
这个大队负责保护我们的社区。
zhègè dàduì fùzé bǎohù wǒmen de shèqū 。
This regiment is responsible for protecting our community.
他们的军大队在山上演习。
tāmen de jūn dàduì zài shānshàng yǎnxí 。
Their army brigade is conducting exercises in the mountains.