lesson 26 nouns, and inter-lesson links

docs/howtostudykorean/unit-1/01-sentences.md

@@ -886,7 +886,7 @@ Common Usages
 - <TTS>이것</TTS> = <span class="md spoiler">this thing</span>
 - <TTS>저것</TTS> = <span class="md spoiler">that thing</span>
 - <TTS>그것</TTS> = <span class="md spoiler">that thing</span>
-- ~는 것 principle (see [Lesson 26](https://www.howtostudykorean.com/unit-2-lower-intermediate-korean-grammar/unit-2-lessons-26-33/lesson-26/))
+- ~는 것 principle (see [Lesson 26](../unit-2/26-describing-nouns-with-verbs.md))
 
 Notes:
 
@@ -1490,7 +1490,7 @@ The way to say “<span class="md spoiler">how are you?</span>” in Korean is:
 
 - 잘 지내세요? <AudioButton src="https://www.howtostudykorean.com/wp-content/uploads/2014/10/Lesson-1new6.mp3" /> = <span class="md spoiler">How are you?</span>
 
-Although this is the most literal way to ask “how are you?” in Korean, it is not as common as the English expression. Korean people love food, and common way to greet somebody is to ask them if they have eaten. The idea of asking questions in Korean is taught in [Lesson 21](https://www.howtostudykorean.com/unit1/unit-1-lessons-17-25-2/lesson-21-asking-questions-in-korean-why-when-where-and-who/).
+Although this is the most literal way to ask “how are you?” in Korean, it is not as common as the English expression. Korean people love food, and common way to greet somebody is to ask them if they have eaten. The idea of asking questions in Korean is taught in [Lesson 21](./21-why-when-where-who.md).
 
 The way to say “<span class="md spoiler">please</span>” in Korean is: