如图，将直线y=﹣x沿y轴向下平移后的直线恰好经过点A（2，﹣4），且与y轴交于点B，在x轴上存在一点P使得PA+PB的值最小，则点P的坐标为____．

某生物小组为了探究甲状腺激素对蝌蚪发育的影响，设计了如下实验步骤：

a．取两个玻璃缸编号为A、B，在A、B两缸内各加入500ml池塘水和等量的蝌蚪饲料．

b．在A、B两缸内加入同时孵化的相同数量的蝌蚪（不能少于5只）．

c．在A缸加入适量的甲状腺激素，B缸不加．

d．保持A、B两缸内水温22﹣25℃，并每天观察和记录蝌蚪生长发育的情况．

请根据实验和所学知识回答下列问题：

（5）根据预测可得出结论：甲状脉激素具有促进蝌蚪发育的作用．

填入适当的词补全对话，每空一词。

A: What's your ____, Madam?

B: I feel very weak. I can hardly do any work, Doctor.

A:____ long have you been like this?

B: Ever since last month.

A: Do you____a headache?

B: No, I ____.

A: Do you sleep well at night?

B: Yes. I sleep very well.

A: Do you often have breakfast?

B: No. I have never had breakfast, and I have____ food for lunch because I would like to be thin.

A: Oh, I see. There's not much wrong  ____ you. You have to take more food and have three meals a day. And do some sports every day. Then you will get____ soon.