The puppy is smaller than the dog.
I am the tallest in my class.
The dogs are the friendliest pets.
Passive Voice:
..."is located";
..."can be seen"
1) Mark is not interested in engineering.
2) He apologized for forgetting their appointment.
3) The hospital in which I was born is being extended.
4) You mustn't smoke on trains.
5) They must be covering something up.