菜鸟急求：不会实现接口成员

初学者急求：不会实现接口成员
代码如下：
using System.Collections.Generic;
using System.Text;
using Wrox.ProCSharp;
using Wrox.ProCSharp.VenusBank;
using Wrox.ProCSharp.JupiterBank;

namespace Wrox.ProCSharp
{
  public interface lBankAccount
  {
  void PayIn(decimal amount);
  bool WithDraw(decimal amount);
  decimal Balance
  {
  get;
  }
  }
}


namespace Wrox.ProCSharp.VenusBank
{
  public class SaverAccount : lBankAccount
  {
  private decimal banlance;

  public void PayIn(decimal amount)
  {
  banlance += amount;
  }

  public bool Withdraw(decimal amount)
  {
  if(banlance>=amount)
  {
  banlance -= amount ;
  return true;
  }

  Console.WriteLine("withDraw attempt failed");
  return false;
  }
   
  public decimal Banlance
  {
  get
  {
  return banlance;
  }
  }

  public override string ToString()
  {
  return string.Format("Verus Bank Saver:Balance={0,6:C}",banlance);
  }
  }  
}


namespace Wrox.ProCSharp.JupiterBank
{
  public class GoldAccount : lBankAccount 
  {

  }
}


namespace ConsoleApplication1
{
  class Program
  {
  static void Main(string[] args)
  {
  lBankAccount venusAccount = new SaverAccount();
  lBankAccount jupiterAccount = new GoldAccount();
  venusAccount.PayIn(200);
  venusAccount.WithDraw(100);
  Console.WriteLine(venusAccount.ToString());
  jupiterAccount.PayIn(500);
  jupiterAccount.WithDraw(600);
  jupiterAccount.WithDraw(100);
  Console.WriteLine(jupiterAccount.ToString());
  }
  }
}


出错：
错误1“Wrox.ProCSharp.VenusBank.SaverAccount”不会实现接口成员“Wrox.ProCSharp.lBankAccount.WithDraw(decimal)”d:\wody\Projects\form\ConsoleApplication1\ConsoleApplication1\Program.cs2418ConsoleApplication1
错误2“Wrox.ProCSharp.VenusBank.SaverAccount”不会实现接口成员“Wrox.ProCSharp.lBankAccount.Balance”d:\wody\Projects\form\ConsoleApplication1\ConsoleApplication1\Program.cs2418ConsoleApplication1
错误3“Wrox.ProCSharp.JupiterBank.GoldAccount”不会实现接口成员“Wrox.ProCSharp.lBankAccount.PayIn(decimal)”d:\wody\Projects\form\ConsoleApplication1\ConsoleApplication1\Program.cs6318ConsoleApplication1
错误4“Wrox.ProCSharp.JupiterBank.GoldAccount”不会实现接口成员“Wrox.ProCSharp.lBankAccount.WithDraw(decimal)”d:\wody\Projects\form\ConsoleApplication1\ConsoleApplication1\Program.cs6318ConsoleApplication1
错误5“Wrox.ProCSharp.JupiterBank.GoldAccount”不会实现接口成员“Wrox.ProCSharp.lBankAccount.Balance”d:\wody\Projects\form\ConsoleApplication1\ConsoleApplication1\Program.cs6318ConsoleApplication1


[解决办法]
using System.Collections.Generic; 
using System.Text; 
using Wrox.ProCSharp; 
using Wrox.ProCSharp.VenusBank; 
using Wrox.ProCSharp.JupiterBank; 

namespace Wrox.ProCSharp 
{ 
public interface lBankAccount 
{ 

void PayIn(decimal amount); 
bool WithDraw(decimal amount); 
decimal Balance 
{ 
get; 
} 
} 
} 


namespace Wrox.ProCSharp.VenusBank 
{ 
public class SaverAccount : lBankAccount 
{ 
private decimal banlance; 

public void PayIn(decimal amount) 
{ 
banlance += amount; 
} 

public bool Withdraw(decimal amount) 
{ 
if(banlance> =amount) 
{ 
banlance -= amount ; 
return true; 
} 

Console.WriteLine("withDraw attempt failed"); 
return false; 
} 

public decimal Banlance 
{ 
get 
{ 
return banlance; 
} 
} 

public override string ToString() 
{ 
return string.Format("Verus Bank Saver:Balance={0,6:C}",banlance); 
} 
}
} 


namespace Wrox.ProCSharp.JupiterBank 
{ 
public class GoldAccount : lBankAccount
{ 
这里没有实现lBankAccount 接口
 private decimal banlance; 

public void PayIn(decimal amount)
{
banlance += amount;
}

public bool Withdraw(decimal amount)
{
if(banlance> =amount)
{
banlance -= amount ;
return true;
}

Console.WriteLine("withDraw attempt failed");
return false;
}

public decimal Banlance
{
get
{
return banlance;
}
}

public override string ToString()
{
return string.Format("Verus Bank Saver:Balance={0,6:C}",banlance);
}
} 
} 


namespace ConsoleApplication1 
{ 
class Program 
{ 
static void Main(string[] args) 
{ 
lBankAccount venusAccount = new SaverAccount(); 
lBankAccount jupiterAccount = new GoldAccount(); 
venusAccount.PayIn(200); 
venusAccount.WithDraw(100); 
Console.WriteLine(venusAccount.ToString()); 
jupiterAccount.PayIn(500); 
jupiterAccount.WithDraw(600); 
jupiterAccount.WithDraw(100); 
Console.WriteLine(jupiterAccount.ToString()); 
} 
} 
} 


[解决办法]
这是个明显的低级错误!!!!!!!!!!!!!!!!!!!

要求实现的那两个东西
bool WithDraw(decimal amount);
decimal Balance
{
 get;
}

一个是被你写成了Withdraw (应该是WithDraw)
另一个是被你写成了Banlance (应该是Balance)

还有
你根本就没有导入 System 命名空间,就写上了Console.WriteLine
[解决办法]

C# code

    public class SaverAccount : IBankAccount     {         void IBankAccount.PayIn(decimal amount)        //必须写明是实现哪个接口的方法        {             //省略        }         bool IBankAccount.Withdraw(decimal amount)         {             //省略        }                   decimal IBankAccount.Banlance         {             //省略        }     }