N보다 더
Use this pattern to compare two things. Put the first thing before '보다' and use '더' when you want to say it is more of something. In the story, '흰색 신발보다 싸고 오래 신을 수 있을 것 같았기 때문이에요' compares the black shoes with the white shoes. You can reuse it like this: '이 신발이 저 신발보다 더 편해 보여요.' It means 'These shoes look more comfortable than those shoes.'
이 신발이 저 신발보다 더 편해 보여요.
These shoes look more comfortable than those shoes.
