A cup of coffee on the tableThere isIt isThey areThere are ​

1 It's a long road. It is a long road. It is the longest road.

2 It is a good student. He is the best student. He's the best student.

3 Students completed a difficult exercise. Students completed a difficult exercise. Students completed the most difficult exercise.

4 I bought a beautiful painting. I bought a beautiful painting. I bought a beautiful painting.

5 My room is very convenient. His room is more convenient. Her room is the most convenient.

6 Nick read an interesting book. Mike read a more interesting book than Nick. Tom read a very interesting book.

Удачи!