The corrected sentence is: "Mom said she had butterflies in her stomach, so I knew she was feeling nervous." The error was literal interpretation — idiom means feeling nervous or anxious: the original sentence "Mom said she had butterflies in her stomach, so I told her to see a doctor." needed to be fixed.

The corrected sentence is: "The teacher said we should put our thinking caps on, so we started thinking carefully." The error was literal interpretation — idiom means to think hard about something: the original sentence "The teacher said we should put our thinking caps on, so everyone went to get a hat." needed to be fixed.

The corrected sentence is: "My brother said he let the cat out of the bag, so we knew the surprise was ruined." The error was literal interpretation — idiom means to reveal a secret accidentally: the original sentence "My brother said he let the cat out of the bag, so we searched the house for the cat." needed to be fixed.

"Hold your horses" comes from telling riders to slow down their horses, so the idiom means to be patient and not rush ahead.

"Getting cold feet" describes the nervous, frozen feeling people get when they become too scared to go through with something, like backing out of a performance.

This idiom pictures solving two problems with a single effort, so "action" fits because it means accomplishing two goals through one deed.

This proverb teaches that words and ideas can change the world more effectively than violence, which is why writing is described as more powerful than fighting.

A good answer includes: It means something that seems bad at first but turns out to be good. For example, missing the bus might be a blessing in disguise if you end up getting a ride and arriving earlier.

A good answer includes: It means that when one bad thing happens, many more tend to follow. People use it to describe a streak of bad luck, like losing your homework and then tripping at recess.