My questions here are in reference to grammar points in Beginner S2 lessons 2 and 3.
Lesson 3 introduced the honorific infix : verb stem + -(으)시 + conjugation. So far, I understand this.
Then, if the conjugation after 시 is standard or intimate politeness, we contract 시 + 어 and we get 셔. I also understand this.
Where I start to get confused is when I see some words that have 세 in them instead of 셔. In fact, the same verb written both ways can be found in these two lessons. For example:
In the Lesson 2 dialogue, 어저씨 says the word " 괜찮으셔 ".
Then in the Lesson 3 dialogue, 직원 says " 괜찮으세요 ".
Another example:
In the Lesson 2 grammar point on honorific infix, the example is given: " 오셔요 ".
The Lesson 3 grammar point on Affirmative Imperative says that this form is the same as regular present conjugation. But they give the example, " 오세요 ".
So my question is...
I can't figure out why 세 is used. If it is a contraction, none of the rules of contractions say that 이 + something else can become 에. It isn't clearly explained in either lesson, it just appears.
Please tell me when to use 세, what it is a contraction of, and when to use 셔. And it would be great if you could change the PDFs so the point is more clear.
Thank you!