2019学年度人教版选修八Unit 5Meeting your ancestors Period 3Learning about Language课件(32张)
2019学年度人教版选修八Unit 5Meeting your ancestors Period 3Learning about Language课件(32张)第5页

③We ________________(find)the bones of tigers and bears in the caves, and we think these were their most dangerous enemies. 结论: 以上三个句子都是_______________; 其构成形 式为__________________。

have been finding

现在完成进行时

have/has been+doing