完形填空
The first note I ever wrote for my mother said "Hi, Mom！Have a nice day！Love，Marie！".I was twelve when I wrote it, and I folded(折叠) the1into her change purse（零钱包）.
My mother worked as a cleaner in a clothing factory. I knew that when she 2meals in the dining hall, she would have to look for change in her purse. I didn't know that she would keep that note, and always carry it with her.
From the day that I3folded the small piece of paper into my mother's change purse, she and I left each other4notes. They would be put in the fridge, under a lamp, or beside the TV set. I5found one hidden in my shoe. From the outside, our notes may have been the records of our days, ideas and wishes. But to my mother and me, they were a lifeline communication with each other that no one else6.
On October 20, 2009, my mother died after a long illness. I stood near her bed, 7her hand. I didn't cry the day my mom died, 8I didn't cry a week later when I went to collect her things. I was so thankful that she no longer had aches and pains.
Recently, I found a note that my mom9me.It was hidden in the10of my favorite childhood book for years. It read "Dear Marie, I love you always. Miss you a lot. Don't forget me. Be happy! Love, Mom" That day, I cried.
2SO3，在一定条件下达到平衡状态，再加入一定量的18O2，则建立新平衡时，含有18O的物质是(假定原平衡体系中不含18O) ( )
