完形填空。
Dear friend,
     I am 1 American school girl. My name is Alice Green. I am twelve. I 2 two brothers. My brothers and I 3 all at school. We go to school 4 Monday 5 Friday. We 6 have classes on 7and Sunday. We don't go to school on weekends. My father and my mother are teachers. They say China is great. I like 8, and I can sing a lot of songs. My brother and I like baseball and basketball. 9do you like? Let's10friends. Please write soon.
Yours,
Alice Green

When John left the room, he ________ take his things.   

-$\frac{1}{2}$的相反数是____ ．

下列各组关于最大公约数的说法中不正确的是（　　）

某地2005年外贸收入为120亿元, 2006年比2005年增加x%, 预计2007年比2006年增加2x%, 则2007年外贸收入达到210亿元, 则可以列出方程是（     ）