Ответ:

1)

A. What are you thinking about these days?

B. Am I thinking about my future career these days?

C. I am not thinking about my future career these days.

2)

A. What are the students doing?

B. Are the students reading?

C. The students aren't reading.

3)

A. What is she wearing?

B. Is she wearing a uniform?

C. She isn't wearing a uniform.

4)

A. What are they talking about?

B. Are they talking about the lecture?

C. They aren't talking about the lecture.

5)

A. What is the teacher speaking to us?

B. Is the teacher speaking English to us?

C. The teacher isn't speaking English to us.

6)

A. What am i looking through at the moment?

B. Am I looking through my notes at the moment?

C. I am not looking through my notes at the moment.