题目

For a long time I saw happiness as a huge banner(横幅)across the finish line of a long race.I felt that only when I __1__ certain things could I finally be happy in my life.Most of the time I felt like a tortoise believing that being slow and __2__ would win the race.At other times I would__3__ like a rabbit trying different side roads at a dangerous __4__hoping to reach that banner a little faster.__5__，I began to see that no matter how long I raced towards it，the banner was never any__6__.I finally decided one day to __7__and take a break.It was then that I saw my __8__ sittin下列物质化学式书写正确的是（ ）A．氢氧化铁Fe（OH）2B．高锰酸钾K2MnO4C．氧化镁MgO2D．硫化钾K2S