Definition: angry and upset because of something bad that has happened that you cannot forget Level: B2
他对错失的机会依然耿耿于怀。
He remained ___bitter about the lost opportunity.
尽管遭到了背叛，她拒绝变得怨恨。
Despite the betrayal, she refused to become ___bitter.
这次失败让他感到极度愤懑不平。
The defeat left him feeling deeply ___bitter.
