Update Reason.md

🔰 Grammar/Obligation.md

@@ -35,6 +35,43 @@ Made with a verb in the negative form (ない) without the ない ending and add
 > {悲|かな}しいのでアイスクリーム食べ==ずには入れれない==。
 > I'm sad so I can't help but eat ice cream.
 
+## こと as "should do"
+
+<div class="usage">
+<div class="left">
+	<p><span class="box">V (dictionary)</span></p>
+	<p><span class="box">V (ない)</span></p>
+</div>
+	<p class="right">+ こと</p>
+</div>
+
+Means "should do". Mostly used to set rules.
+
+> [!info] Example
+> ここに{車|くるま}を{止|と}めない==こと==です。
+> Don't park your car here.
+
+## ことはない
+
+This has two meanings:
+* it is not necessary to
+* it never happens
+
+Used with a verb in the dictionary form.
+
+> [!info] Example
+> {走|はし}る==ことはない==。まだ{時間|じかん}がある。
+> There's no need to run. There's still time.
+
+## ことになっている
+
+This form is used to express rules or expectations.
+Used with dictionary (る) and negative (ない) form of verbs.
+
+> [!info] Examples
+> {指|ゆび}で食べない==ことになっている==。
+> You're not supposed to eat with your fingers.
+
 ## Must
 
 ### なくちゃ・なきゃ
@@ -74,7 +111,7 @@ In casual contexts, can be shortened as ないと.
 > 今日は{勉強|べんきょう}し==ないといけない==。
 > I have to study today.
 
-## べきだ
+### べきだ
 
 Means "should do", "must do".
 Used with verbs.
@@ -142,7 +179,7 @@ Can also be used as なくていい.
 > 今日はレストランで{手伝|て|つ}わ==なくてもいい==。
 > You don't have to help out at the restaurant today (it's okay if you don't help at the restaurant today).
 
-## べきではない・べきじゃない
+### べきではない・べきじゃない
 
 The contrary of べきだ is べきではない・べきじゃない.
 

🔰 Grammar/Opposition.md

@@ -91,6 +91,47 @@ https://bunpro.jp/grammar_points/%E3%82%8F%E3%82%8A%E3%81%AB
 lots of things are similar
 
 
+## ことは～が
+
+<div class="usage">
+<div class="">
+	<p><span class="box">V</span></p>
+</div>
+	<p class="r">+ ことは + </p>
+<div class="">
+	<p><span class="box">V</span></p>
+</div>
+	<p class="r">+ が</p>
+</div>
+<div class="usage">
+<div class="">
+	<p><span class="box">い-Adj</span></p>
+</div>
+	<p class="r">+ ことは + </p>
+<div class="">
+	<p><span class="box">い-Adj</span></p>
+</div>
+	<p class="r">+ が</p>
+</div>
+<div class="usage">
+<div class="">
+	<p><span class="box">な-Adj + な</span></p>
+</div>
+	<p class="r">+ ことは + </p>
+<div class="">
+	<p><span class="box">な-Adj</span></p>
+</div>
+	<p class="r">+ が</p>
+</div>
+⚠ It must be the same verb and adjective at both end!
+
+Means "although".
+
+> [!info] Example
+> {勉強|べんきょう}する==ことは==する==が==、まだ{下手|へた}です。
+> Although I study everyday, I'm still bad at it.
+
+
 
 # TODO
 

🔰 Grammar/Reason.md

@@ -24,6 +24,14 @@ It is more objective than から: it expresses a situation that exists, and that
 See [[🔰 Particles (2)#Because]].
 It is more subjective than ので: it expresses more personal needs/actions/opinions.
 
+## ことから
+
+Means "based on the fact that". Most formal than から, and puts an emphasis on it being true (objective information).
+
+> [!info] Example
+> {部屋|へや}から{音|おと}がある==ことから==、{誰|だれ}かいるはずです。
+> From the fact that there is sound coming from the room, someone must be there.
+
 ## んです・のです
 
 <div class="usage">