①2个硫原子____;②氯酸钾中的阳离子____;
③“Fe2+”中数字“2”表示的意义是____;
④2个五氧化二磷分子____;⑤最简单的有机物____.
下列各式中,是方程的为( ).
①2x-1=5 ②4+8=12 ③5y+8 ④2x+3y=0 ⑤2x2+x=1 ⑥2x2-5x-1
— What are you going to do if it______ tomorrow?
—I haven't thought about it.