DateTime dtStart = DateTime.Now;
string ver = string.Empty;

SqlConnectionStringBuilder cnSettings = new SqlConnectionStringBuilder(
      "Data Source=.;"
    + "Database=PUBS;"
    + "Asynchronous Processing=true;"
    + "Integrated Security=True;"
    + "Max Pool Size=5"
);

using (SqlConnection cn1 = new SqlConnection(cnSettings.ConnectionString))
using (SqlConnection cn2 = new SqlConnection(cnSettings.ConnectionString))
using (SqlConnection cn3 = new SqlConnection(cnSettings.ConnectionString))
{
    using (SqlCommand cmd1 = cn1.CreateCommand())
    using (SqlCommand cmd2 = cn2.CreateCommand())
    using (SqlCommand cmd3 = cn3.CreateCommand())
    {
        cmd1.CommandText = "WaitFor Delay '00:00:10' Select '1st Query
'";
        cmd2.CommandText = "WaitFor Delay '00:00:10' Select '2nd Query
'";
        cmd3.CommandText = "WaitFor Delay '00:00:10' Select '3rd Query
'";
        cn1.Open();
        cn2.Open();
        cn3.Open();

        IAsyncResult ar1 = cmd1.BeginExecuteReader();
        IAsyncResult ar2 = cmd2.BeginExecuteReader();
        IAsyncResult ar3 = cmd3.BeginExecuteReader();

        ar1.AsyncWaitHandle.WaitOne();
        using (SqlDataReader dr1 = cmd1.EndExecuteReader(ar1))
        {
            while (dr1.Read())
            {
                ver += dr1[0].ToString();
            }
        }

        ar2.AsyncWaitHandle.WaitOne();
        using (SqlDataReader dr2 = cmd2.EndExecuteReader(ar2))
        {
            while (dr2.Read())
            {
                ver += dr2[0].ToString();
            }
        }
    

        ar3.AsyncWaitHandle.WaitOne();
        using (SqlDataReader dr3 = cmd3.EndExecuteReader(ar3))
        {
            while (dr3.Read())
            {
                ver += dr3[0].ToString();
            }
        }
    }
}
DateTime dtEnd = DateTime.Now;
ver += "Running Time: " + (dtEnd - dtStart).ToString() + " Seconds
";
Label1.Text = ver;