某种群中，基因型AA个体占25％，Aa个体占60％，那么基因A和a的频

搜题请搜索小程序“爱下问搜题”

问题单项选择题

某种群中，基因型AA个体占25％，Aa个体占60％，那么基因A和a的频率为（）

A.50％和50％

B.25％和75％

C.55％和45％

D.30％和70％

答案

参考答案：C

句型转换

句型转换。

1.We should allow teenagers to swim in the river.（改为被动语态）

Teenagers to swim in the river

2. She said something important to me yesterday.（改为否定句）

She important to me yesterday.

3.1 was so anxious that I couldn't sleep.（改为同义句）

1 was ____ anxious ____ sleep.

4．They are very friendly.（改为同义句）

They are ____ to ____ .

5. I spent two hours doing my homework last night.（对画线部分提问）

____ did you spend doing your homework last night?

问答题简答题

电风扇能把空气吹凉吗？