下列对联都与诗人有关，其中与其他三联所写的诗人不同的一项是（     ）

Dear Abby，

    I'm a helpless mother. My son Tom is 15 years old. I find that the older he grows， the less we talk. I feel very sad and I really need help.

    My first problem is about his hobbies. He spends almost all his spare time on computer games. When he gets home， he always turns on the computer and closes the door. I'm getting worried about him， especially when his English teacher tells me he always gets low marks in the English exams.

    Second， he likes new technology， but I don't have enough money and I can't afford all the things he wants.

    Recently， I've found that he is always alone. I've never seen him talking to his friends on the phone or going out with anyone on weekends. That is the last problem I have.

    What should I do to help him? Please give me some advice.

A helpless mother

①任何无理数都是无限不循环小数；

②有理数与数轴上的点一一对应；

③在1和3之间的无理数有且只有 $\sqrt{2}，\sqrt{3}，\sqrt{5},\sqrt{7}$ 这4个；

④ $\frac{\pi }{2}$ 是分数，它是有理数；

⑤由四舍五入得到的近似数7.30表示大于或等于7.295，而小于7.305的数．

其中正确的个数是（   ）