挑战习题
1/5单选题
难度:

1.在FeO中,铁元素为_____价
A +2
B +1
C -2
D -1
提示1:
IOawp+WFg+e0oOeahOWMluWQiOS7t+aYry0y
提示2:
IOWFg+e0oOWMluWQiOS7t+S7o+aVsOWSjOS4ujA=
正确答案:QQ==
WC0yPTA8YnI+WD0y