从修辞角度看，下列句子中不同类的一项是（    ）

有三种白色粉末，分别是碳酸钠、氯化铁和氯化钠中的一种．请设计一个实验方案，把这三种粉末区分开来．叙述实验操作、预期现象和结论．

补全对话；从方框内所给句子中选择恰当的句子完成下面对话，并将其代表字母涂（填）在答题卡（纸）的相应位置。

( At the doctor's)

A: Good morning.

B: Morning doctor.

A:____ 

B: I'm not feeling very well.

A: Oh, let me see… ____  You are just overweight.

B: Really? But I don't eat too much.

A:____  You often eat sweet food and meat, don't you?

B: Yes, both of them.

A: To keep fit, you'd better eat less sugar but more vegetables. ____ 

B: OK, I'll do like that.

A: ____ .

B: Thank you very much.

①∠AGD=112.5°；②tan∠AED= $\sqrt{2}$ +1；③四边形AEFG是菱形；④S_△ACD= $\sqrt{3}$ S_△OCD．

其中正确结论的序号是____．（把所有正确结论的序号都填在横线上）