ad·vance guard
noun/ədˌvɑːns ˈɡɑːd/
/ədˌvæns ˈɡɑːrd/
(also advanced guard)
[countable + singular or plural verb]- a group of soldiers who go somewhere to make preparations before other soldiers arrive
先遣部队 - (figurative) White blood cells may be considered the advance guard of the immune system.
白细胞可以被认为是免疫系统的前卫。
- (figurative) White blood cells may be considered the advance guard of the immune system.