磷酸萃取通常发生包裹反应的游离硫酸根浓度均处于（）。
A、1.5～2.5%
B、2.5～3.5%以上
C、3.5%以上
D、1.5%以下
参考答案：C
函数Str$(256.36)的值是______。
改错，选出错误的选项并改正。
( ) 1. I was watching TV when I hear the news. I was excited. _______________
A B C D
( ) 2. Jill is sleeping when someone called him. _______________
( ) 3. I think Chinese is more easier than maths. _______________
( ) 4. This work is very harder than that one. _______________
( ) 5. The book is enough easy for him to read. _______________
( ) 6. Which city is largest, Beijing or Shanghai? _______________
( ) 7. Maybe I can go to the Olympics on the future. _______________
( ) 8. When the bells rang, I was cheer. _______________
( ) 9. Jack comes to school early than John. _______________
( ) 10. When we meet older people, we should shape hands. _______________
