Make the following sentences (a) negative, (b) interrogative

(a) negative

I have not finished the work.

He has not written a letter.

The cat has not drunk its milk.

They have not understood the lesson.

Richard has not gone to the Zoo.

I did not finish the work yesterday.

He did not write a letter last week.

Richard did not go to the Zoo last week.

(b) interrogative

Have I finished the work?

Has he written a letter?

Has the cat drunk its milk?

Have they understood the lesson?

Has Richard gone to the Zoo?

Did I finish the work yesterday?

Did he write a letter last week?

Did Richard go to the Zoo last week?

Negative
1.I have not finished the work
2.He hasn't written a letter
3.The cat hasn't drunk its milk
4.They have not understood the lesson
5.Richard hasn't gone to the Zoo