Correct these sentences. Write their correct full variants:
1. The Kuala Lumpur Tower is more modern in the world.
2. Paris is the quieter than New York.
3. Jeff is the clever student in his group.

1. The Kuala Lumpur Tower is one of the most modern towers in the world.

Explanation: When comparing something to others, we use the superlative form. So, instead of saying "more modern," we say "one of the most modern" to indicate that the Kuala Lumpur Tower is one of the most modern towers compared to others in the world.

2. Paris is quieter than New York.

Explanation: When comparing two things, we use the comparative form. In this case, we are comparing the noise levels of Paris and New York, so we use "quieter" to show that Paris has a lower level of noise compared to New York.

3. Jeff is the cleverest student in his group.

Explanation: When comparing the intelligence or abilities of people, we use the superlative form. Instead of saying "the clever student," we say "the cleverest student" to indicate that Jeff is the most intelligent or skillful student in his group.