1. There are 45 black rabbits and 225 white rabbits.

Let x black rabbits use it and 5x white rabbits use it.

(5x+20)=7*(x- 10)

Solve it, x=45, there are 225 white rabbits.

English

1. (one, 1) (two, three) (three, two) (four, four)

I am Mary's son. I am Mary's son.

They are my aunt's husbands. She is my aunt's husband.

4. Clock. clock

5. This man is in China. That man is in China.