How to merge or combine two combobox in one comb box

Question

I have two combo box controls

First combo box show Arabic membership

Second combo box show English member ship

I need to merge two combo box in one combo box show both of them

my code as below

MemberAR sheet and MemberEN sheet have two fields

MemberID , MemberName 

public DataTable ShowExcelDataArabic()
        {

            OleDbConnection con = new OleDbConnection(connection);


                con.Open();
               string str = "select * from [MemberAR$]";
                OleDbCommand com = new OleDbCommand();
                com = new OleDbCommand(str, con);
                OleDbDataAdapter oledbda = new OleDbDataAdapter();
                oledbda = new OleDbDataAdapter(com);
                DataSet ds = new DataSet();
                ds = new DataSet();
                oledbda.Fill(ds, "[MemberAR$]");
                con.Close();
                DataTable dt = new DataTable();
                dt = ds.Tables["[MemberAR$]"];
                return dt;


        }
public DataTable ShowExcelDataEnglish()
        {

            OleDbConnection con = new OleDbConnection(connection);


            con.Open();
            string str = "select * from [MemberEN$]";
            OleDbCommand com = new OleDbCommand();
            com = new OleDbCommand(str, con);
            OleDbDataAdapter oledbda = new OleDbDataAdapter();
            oledbda = new OleDbDataAdapter(com);
            DataSet ds = new DataSet();
            ds = new DataSet();
            oledbda.Fill(ds, "[MemberEN$]");
            con.Close();
            DataTable dt = new DataTable();
            dt = ds.Tables["[MemberEN$]"];
            return dt;


        }

 

in load event of windows form

 combo box Arabic membership and combo box English member ship as following :

 

QrClasses qrc = new QrClasses();
                DataTable dt = qrc.ShowExcelDataArabic();
                int c = 0;
                comboBox1.Items.Insert(0, "???? ?????");
                comboBox1.SelectedIndex = 0;
                for (c = 0; c <= dt.Rows.Count - 1; c++)
                {

                    comboBox1.Items.Add(dt.Rows[c].ItemArray[1]);
                }


                DataTable dt2 = qrc.ShowExcelDataEnglish();
                int d = 0;
                comboBox2.Items.Insert(0, "Select Member");
                comboBox2.SelectedIndex = 0;
                for (d = 0; d <= dt2.Rows.Count - 1; d++)
                {

                    comboBox2.Items.Add(dt2.Rows[d].ItemArray[1]);
                }