A:SO2
B:Cl-
C:Fe3+
D:NO
下列离子方程式的书写正确的是( )
根据问句选答句。
How old are you?____ A. I'm 10.
Happy birthday!____ B. Five.
How are you?____ C. Thank you.
How many boxes?____ D. I'm fine, thank you.
I have a ruler.____ E. Me, too.
最先证明地球是个球体的事件是( )