step into the breach

US /stɛp ˈɪntu ðə briːtʃ/
UK /stɛp ˈɪntu ðə briːtʃ/
"step into the breach" picture
1.

挺身而出, 填補空缺

to take action when another person or group is unable to, or to fill a gap in a difficult situation

:
When the lead actor fell ill, his understudy had to step into the breach.
當主角生病時,他的替補不得不挺身而出
The volunteers had to step into the breach when the regular staff went on strike.
當正式員工罷工時,志願者不得不挺身而出