Answer:
so for example, chicken is 닭. and this word has ㄹ and ㄱ.
you can't put ㅅ and ㅂ together because they can't make sound if we combine ㅅ and ㅂ.
Here are some examples.
읽다/ilgda
짧다/jjalbda
앉다/anjda
많다/anjda
밝다/balgda
옮기다/olmgida
(also I left a comment at your college thing that you wrote.)