问题描述：
1：有二个同心圆所组成的圆环的面积为较小圆面积的七分之九,求较大圆与较小圆的半径比
用所给词的适当形式填空 1：These_____(not be)their English books.
2:The man is my ____(mother)uncle．
3:Are those your＿＿（dictionary）?
4：Can you ＿＿（bring）your new picture here?
用所给词的适当形式填空 1：These_____(not be)their English books.
2:The man is my ____(mother)uncle．
3:Are those your＿＿（dictionary）?
4：Can you ＿＿（bring）your new picture here?
问题解答：
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