方程2x²-3x+1=0化为(x+a)²=b的形式，正确的是（    ）

小李同学在百米赛跑时，在前8s内加速跑完了36m，接着保持8m/s的速度跑完全程，则他百米赛跑的成绩是____ s．百米赛跑的平均速度　____ m/s．春天到了，学校院内的桃花盛开了，同学们在很远的地方就能闻到花香，这是____ 现象，这个现象说明了____ ．

     A woman is having some trouble(患病) with her eyes, so she goes to see the doctor. He is a new doctor and doesn’t know her, so he asks some questions and one of them is, “How old are you?”

     The woman says, “I don’t know, doctor, but let me think about it.” She thinks for a few minutes and then says, “Yes, I know now, doctor! When I marry(结婚), I am eighteen years old, and my husband is thirty. Now my husband is sixty. And that is twice(两倍) thirty. So I am twice eighteen. That’s thirty-six, isn’t it?”