（共40题、总分40分）1.( ) some mammals came to live in the sea is not known (本题分

分类: 作业答案 • 2022-04-08 11:49:32

问题描述：

答

When最好.
如果填whether或if搭配or not.
Where后面已经有in the sea.
Who不对,已经有mammals.