The ugly incidents of the Civil War are water under the bridge. This means that the incidents

Analyze the question The question tests your knowledge of idioms. The idiom "water under the bridge" is used to describe something that happened in the past and is no longer important or worth worrying about.

Explain the concept "Water under the bridge" refers to water that has already flowed past and cannot come back. In the same way, past events, especially unpleasant ones like quarrels, offences, or wars, are now behind us. We have moved on, and they no longer matter or trouble us.

Solution: test each option

• A. continue to haunt us: This is the opposite meaning. If something is water under the bridge, it no longer troubles us.
• B. have been experienced again: The idiom says nothing about repetition. Water that has passed does not return.
• C. have been forgotten: This fits best. The incidents belong to the past and are no longer a source of concern. The idea of letting go or moving on matches "forgotten".
• D. cannot be wished away: This also suggests the events are still a lasting burden, which contradicts the idiom.

Answer The correct option is C. have been forgotten.

Tip For idiom questions, picture the literal image. Water that flows under a bridge is gone and will not return, so the matter is over and past. Similar idioms are "let bygones be bygones" and "bury the hatchet". Any option about something continuing or returning is likely a trap.