The Korean time expression -(으)ㄴ 지 you use to express how much time has passed since an event or action. 되다 and 넘다 often appear following the first clause.
The form -(으)ㄴ/는 것 같다 is a more important Korean grammar forms to know. It not only expresses supposition, It can also be used to be more polite.
-(으)ㄴ/는데 form with which you can express a contrast between two parts of a sentence. You can also use it to give background info or reason for what you say.
-(으)ㄴ/는데요 is an important and flexible Korean grammar topic. you can use it to express disagreement, your surprise or your expectation of a response.
-(으)ㄹ 거예요 is a form most people know as the Korean future tense, but you can also use this form to express one of your suppositions.
The form -(으)ㄹ게요 is a simple way to express your intent or to make a promise. This form is used in conversations with friends or family though.
The form -(으)ㄹ까요 is a form with multiple uses. You can use it express your supposition in the form of question, ask for an opinion or make a suggestion.
The form -(으)ㄹ래요 is a casual form to either ask for someone’s decision, opinion or intentions; or to express your intention, plan or decision.
The formal form -(으)ㅂ시다 let’s you make suggestions or proposals to do something to others. It is a form with a few restrictions on when it is proper to use.
The form -(으)니까 allows you to express the reason or cause of something. Or you can use it to express your discovery after performing a certain action.