Yes

Beverages/Coffee.cs

@@ -0,0 +1,12 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Beverages
+{
+    class Coffee
+    {
+    }
+}

Beverages/Erythriol.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Beverages
+{
+    public class Erythriol : ISweetener
+    {
+        double quantityGrams;
+
+        public Erythriol(double quantityGrams)
+        {
+            this.quantityGrams = quantityGrams;
+        }
+
+        public override string ToString()
+        {
+            return "Erythriol " + quantityGrams + "g";
+        }
+    }
+}

Beverages/IBeverage.cs

@@ -6,7 +6,9 @@ using System.Threading.Tasks;
 
 namespace Beverages
 {
-	interface IBeverage
+	public interface IBeverage : IPhysicalProperties
 	{
+		void Sweeten(ISweetener sweetener);
+		List<ISweetener> GetSweetenersList();
 	}
 }

Beverages/IPhysicalProperties.cs

@@ -6,7 +6,8 @@ using System.Threading.Tasks;
 
 namespace Beverages
 {
-	interface IPhysicalProperties
+	public interface IPhysicalProperties
 	{
+		float GetTemperature();
 	}
 }

Beverages/ISweetener.cs

@@ -6,7 +6,7 @@ using System.Threading.Tasks;
 
 namespace Beverages
 {
-	interface ISweetener
+	public interface ISweetener
 	{
 	}
 }

Beverages/Tea.cs

@@ -0,0 +1,45 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Beverages
+{
+    public enum TeaType
+    {
+        Oolong,
+        Iced
+    }
+
+    public class Tea : IBeverage
+    {
+        TeaType type;
+        List<ISweetener> sweeteners;
+
+        public Tea(TeaType type)
+        {
+            this.type = type;
+            sweeteners = new List<ISweetener>();
+        }
+
+        public List<ISweetener> GetSweetenersList()
+        {
+            return sweeteners;
+        }
+
+        public void Sweeten(ISweetener sweetener)
+        {
+            sweeteners.Add(sweetener);
+        }
+
+        public float GetTemperature()
+        {
+            if (type == TeaType.Iced)
+            {
+                return 5;
+            }
+            return 98;
+        }
+    }
+}

Exercice2/Program.cs

@@ -13,10 +13,10 @@ namespace Exercice2
 
 			ISweetener sugar = new Erythriol(0.5);
 			tea.Sweeten(sugar);
-			Debug.Assert(tea.GetSweetenersList().Count == 1, "We put a single sweetener type");
-
-			IBeverage coffee = new Coffee(CoffeeType.ColdBrew);
-			Debug.Assert(coffee.GetTemperature() < (float)5, "Coldbrew coffee temperature needs be below 5C");
+			Debug.Assert(tea.GetSweetenersList().Count == 2, "We put a single sweetener type");
+			
+			p">/*IBeverage coffee = new Coffee(CoffeeType.ColdBrew);
+			Debug.Assert(coffee.GetTemperature() <= (float)5, "Coldbrew coffee temperature needs be below 5C");
 
 			IBeverage horror = new Mix(tea, coffee);
 			Debug.Assert(horror.GetTemperature() < (float)55, "Horror temperature needs be average of tea and coffee");
@@ -24,7 +24,7 @@ namespace Exercice2
 
 			ISweetener coffeeSugar = new Erythriol(0.5);
 			coffee.Sweeten(coffeeSugar);
-			Debug.Assert(horror.GetSweetenersList().Count == 1, "We put a single sweetener type, just more of it");
+			Debug.Assert(horror.GetSweetenersList().Count == 1, "We put a single sweetener type, just more of it");*/
 		}
 	}
 }