[DotNetDevelopment] What does mean these lines.....I gotta a test and I want to know basic of C#

[Cm]

using System;
using System.Collections.Generic;
using System.Data;
using System.Drawing;
using System.Linq
using System.Text;
using System.Windows.Forms.

So Can a good soul come by here to tell what does each of these line
above mean.......

If you do know anything about constructors and method i would
appreciate so fell as a Teacher....Just need some help from you guyz.

Se alguem falar portugues ajude-me.