理想变压器实现阻抗变换，次级接RL，变比为n，这初级输入电阻等效为（）。 A.A B

在探究“光对鼠妇生活的影响”的实验中，把同样多的鼠妇同时放在较暗和较亮的环境中。下列哪种曲线能表示较暗环境中鼠妇的数量变化？                   （ ）

A: Have you seen Li Ling these days?

B: No, she’s gone to Jilin 1. __________ her grandfather.

A: Has she ever been there before?

B: Yes, she lived there before she came here.

A: Have you 2. __________ her?

B: Yes, I’ve just received a letter from her.

A: 3. __________?

B: She said she had a very good time and would 4. __________ there for another week.

A: What else did she say?

B: She also wanted me to give her best 5. __________ to you.

A: It was very nice of her to say so.

果蝇的长翅和残翅是由一对等位基因V和v控制的，果蝇的正常发育是在20℃~25℃条件下完成。将果蝇培养在20℃以上的条件下，残翅果蝇的后代（F1）会出现长翅性状，此现象可以解释为（）

A、环境因素可以引起基因重组

B、表现型是基因型与环境因素共同作用的结果

C、环境因素可以引起基因突变

D、环境因素可以引起染色体变异

高血钾型肾小管性酸中毒（）

A.经常发生高血钾

B.易形成肾结石

C.可出现肾性糖尿

D.尿中HCO₃^-增多

E.醛固酮分泌增多

大隐静脉曲张患者，根据其解剖生理特点下列哪项是判断是否手术的关键

A．Pratt试验

B．Trendelenburg试验

C．Penhes试验

D．Burger试验

E．毛细血管充盈试验