switched

"My friend told me there was something in the box, but I didn't know what it was yet. "

"He discovered penicillin largely accidentally."

"The specified dress code for the party included a formal gown and black tie. "

"He behaved unreasonably."

"My family has a different ideal for my future than I do. "

"Suddenly, the heavens opened and we all got drenched."

"The children excitedly opened their birthday presents. "

"There were many laughing children running on the school grounds."

"The electrician fixed the broken lights in our kitchen. "

"It is generally known that the Earth is round."

"The transfer of the student to a different class was announced in a school memo. "

"All in all, it was an even exchange."