题干
— Dad, must we wait until the light become green?
— Yes, I'm afraid we __________. That's the traffic rule.
A：can
B：may
C：have to
答案(点此获取答案解析）
C
— Dad, must we wait until the light become green?
— Yes, I'm afraid we __________. That's the traffic rule.
A：can
B：may
C：have to
4NaOH(熔) 
4Na +O2↑+ 2H2O；
Fe3O4＋2H2↑十4Na↑。下列有关说法正确的是 ( )
