только одно предложение Change the Direct Speech into Indirect.

The students ask the teacher: "What must we do with this exercise?"​

ASK: The students ASK the teacher what they must do with this exercise.

* we --> they

* порядок слов , как в утверждении ​

ASKED: The students askED the teacher what THEY HAD TO DO  with THAT exercise.

* must --> had to

* this --> that

* порядок слов , как в утверждении ​