Cathy’s parents got married twenty-five years ago.（改为同义句）
Cathy’s parents ________ ________ married for twenty-five years.
We will hold a class meeting to talk about team work next Friday．（改为被动语态）
A class meeting will to talk about team work next Friday．
Grace does online shopping four times a month．（对划线部分提问）
does Grace do online shopping？
John went to church with his brother last Sunday moring．（改为否定句）
John to church with his brother last Sunday morning．
PM 2.5 does harm to people's health and the environment．（保持句意基本不变）
PM 2.5 is people's health and the environment．
"Have you ever been in a hot air ballon？"Melissa asked her mom．（改为宾语从句）
Melissa asked her mom she ever been in a hot air balloon．