diff --git a/flash_cards.py b/flash_cards.py
index 36edb2c..bbe68d1 100644
--- a/flash_cards.py
+++ b/flash_cards.py
@@ -193,10 +193,10 @@ def memorize(card_type, card_id=None):
                            card_type=card_type,
                            short_answer=short_answer, tags=tags)
 
-@app.route('/memorize_know')
-@app.route('/memorize_know/<card_id>')
-@app.route('/memorize_know/<card_type>')
-def memorize_know(card_type, card_id=None):
+@app.route('/memorize_known')
+@app.route('/memorize_known/<card_id>')
+@app.route('/memorize_known/<card_type>')
+def memorize_known(card_type, card_id=None):
     tag = getTag(card_type)
     if tag is None:
         return redirect(url_for('cards'))
@@ -211,7 +211,7 @@ def memorize_know(card_type, card_id=None):
     short_answer = (len(card['back']) < 75)
     tags = getAllTag()
     card_type = int(card_type)
-    return render_template('memorize_know.html',
+    return render_template('memorize_known.html',
                            card=card,
                            card_type=card_type,
                            short_answer=short_answer, tags=tags)
@@ -459,6 +459,15 @@ def get_card_already_known(type):
     cur = db.execute(query, [type])
     return cur.fetchone()
 
+@app.route('/mark_unknown/<card_id>/<card_type>')
+def mark_unknown(card_id, card_type):
+    if not session.get('logged_in'):
+        return redirect(url_for('login'))
+    db = get_db()
+    db.execute('UPDATE cards SET known = 0 WHERE id = ?', [card_id])
+    db.commit()
+    flash('Card marked as unknown.')
+    return redirect(url_for('memorize_known', card_type=card_type))
 
 if __name__ == '__main__':
     app.run(host='0.0.0.0')
diff --git a/templates/layout.html b/templates/layout.html
index dd6df82..37a5874 100644
--- a/templates/layout.html
+++ b/templates/layout.html
@@ -29,7 +29,7 @@
                                 <li><a href="{{ url_for('list_db') }}">list database</a></li>
                                 <li><a href="{{ url_for('create_db') }}">create database</a></li>
                                 <li><a href="{{ url_for('memorize', card_type='1') }}">memorize</a></li>
-                                <li><a href="{{ url_for('memorize_know', card_type='1') }}">memorize known items</a></li>
+                                <li><a href="{{ url_for('memorize_known', card_type='1') }}">memorize known items</a></li>
                                 <li>&nbsp;&nbsp;&nbsp;&nbsp;</li>
                                 <li><a href="{{ url_for('logout') }}">log out</a></li>
                             {% endif %}
diff --git a/templates/memorize_know.html b/templates/memorize_known.html
similarity index 85%
rename from templates/memorize_know.html
rename to templates/memorize_known.html
index 42c0269..d09ea76 100644
--- a/templates/memorize_know.html
+++ b/templates/memorize_known.html
@@ -5,7 +5,7 @@
         <div class="col-xs-12 text-center">
             <div class="btn-group btn-group-lg" role="group" aria-label="card type">
                 {% for tag in tags %}
-                    <a href="{{ url_for('memorize_know', card_type=tag.id) }}" class="btn btn-{{ "primary" if card_type == tag.id else "default" }}">{{tag.tagName}}</a>
+                    <a href="{{ url_for('memorize_known', card_type=tag.id) }}" class="btn btn-{{ "primary" if card_type == tag.id else "default" }}">{{tag.tagName}}</a>
                 {% endfor %}
             </div>
         </div>
@@ -54,13 +54,13 @@
             </a>
             &nbsp;
             &nbsp;
-            <a href="{{ url_for('mark_known', card_id=card.id, card_type=card_type) }}" class="btn btn-success btn-lg">
+            <a href="{{ url_for('mark_unknown', card_id=card.id, card_type=card_type) }}" class="btn btn-success btn-lg">
                 <i class="fa fa-check"></i>
-                I Know It
+                I Unknow It
             </a>
             &nbsp;
             &nbsp;
-            <a href="{{ url_for('memorize_know', card_type=card_type) }}" class="btn btn-primary btn-lg">
+            <a href="{{ url_for('memorize_known', card_type=card_type) }}" class="btn btn-primary btn-lg">
                 Next Card
                 <i class="fa fa-arrow-right"></i>
             </a>