LINQ在Mac OSX 104.4上不能与MyDeals/Muno的最后版本一起工作

我正在尝试执行一个简单的测试代码:

using System;
using System.IO;
using System.Linq;
using System.Collections.Generic;

namespace TestMono
{
    public class TesterManager
    {
        public TesterManager ()
        {
            Console.WriteLine("Test");
            Path.GetTempPath();

            foreach (var i in new int[] { 1, 2, 3, 4, 5}.Where(n => n % 2 == 0))
        {
            Console.WriteLine(i);
        }

            List<string> ar= new List<string>();
            ar.Add("1"); ar.Add("2");


            var lb = ar.Where(n => n=="2");
        }
    }
}

编译代码时,我有两个错误:

Esecuzione compilazione principale...
/Library/Frameworks/Mono.framework/Versions/2.6.4/bin/gmcs /noconfig "/out:/Users/roberto/Projects/TestMono/TestMono/bin/Debug/TestMono.exe" /nologo /warn:4 /debug:+ /debug:full /optimize- /codepage:utf8 /platform:x86 "/define:DEBUG"  /t:exe "/Users/roberto/Projects/TestMono/TestMono/TesterManager.cs" "/Users/roberto/Projects/TestMono/TestMono/Main.cs" 
Compilation failed: 2 error(s), 0 warnings

/Users/roberto/Projects/TestMono/TestMono/TesterManager.cs(15,70): error CS1061: Type `int[]' does not contain a definition for `Where' and no extension method `Where' of type `int[]' could be found (are you missing a using directive or an assembly reference?)
/Users/roberto/Projects/TestMono/TestMono/TesterManager.cs(24,37): error CS1061: Type `System.Collections.Generic.List<string>' does not contain a definition for `Where' and no extension method `Where' of type `System.Collections.Generic.List<string>' could be found (are you missing a using directive or an assembly reference?)

我在项目属性中设置了mono/.net 3.5,并且我有mono和monobeloper的最新版本。我不明白那是怎么回事!