what does object sender, EventArgs e Means how they helpul

 Hello I am new to ASP.NET.
In every event it looks like
For example take an event

protected void LinkButton1_Click(object sender, EventArgs e)
{
 LinkButton lb = (LinkButton)sender;
}
 what does object sender,EventArgs e mean and (linkButton)sender means.
kindly explain me.
 
bye.

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