1 . Identifying costumes of different ethnic groups is one of the most interesting things when learning about them 2 . Machinery has made farm production easily and has liberated labor work ( Tìm lỗi sai và sửa )

1`.` Identifying costumes of different ethnic groups is one of the most interesting thingswhen learning about them

⇒ Identifying costumes of different ethnic groups is one of the most interesting things to learn about them

Giải thích : Do `when + to V`
2. Machinery has made farm production easily and has liberated labor work

⇒ Machinery has made farm production easy and has liberated labor work

Giải thích : Do` make+N+adj`