stand by

Từ điển Oxford Advanced Learner 8th

ˌstand ˈby derived
1. to be present while sth bad is happening but not do anything to stop it
• How can you stand by and see him accused of something he didn't do?
related noun ↑bystander
2. to be ready for action
• The troops are standing by.
related noun ↑standby
Main entry: ↑stand_derived