CAN YOU SHORTEN THE FOLLOWING CODE  
function addTimestamp2(e) {
// https://www.youtube.com/watch?v=548dD3iXetg&t=265s&ab_channel=LearnGoogleSheets%26ExcelSpreadsheets

var startRow3 = 6;
var targetColumn3 = 3;

var startRow4 = 6;
var targetColumn4 = 4;

var startRow5 = 6;
var targetColumn5 = 5;

var startRow6 = 6;
var targetColumn6 = 6;

var startRow7 = 6;
var targetColumn7 = 7;

var startRow8 = 6;
var targetColumn8 = 8;

var startRow9 = 6;
var targetColumn9 = 9;
////////////////////////////////////
var startRow11 = 6;
var targetColumn11 = 11;

var startRow12 = 6;
var targetColumn12 = 12;

var startRow13 = 6;
var targetColumn13 = 13;

var startRow15 = 6;
var targetColumn15 = 15;

var startRow14 = 6;
var targetColumn14 = 14;

var startRow15 = 6;
var targetColumn15 = 15;

var startRow16 = 6;
var targetColumn16 = 16;
/////////////////////////////////////
var startRow18 = 6;
var targetColumn18 = 18;

var startRow19 = 6;
var targetColumn19 = 19;

var startRow20 = 6;
var targetColumn20 = 20;
var ws = "جدول المتابعة";

// get modified row and colum
var row = e.range.getRow();
var col = e.range.getColumn();

if(col === targetColumn3 && row >= startRow3 && e.source.getActiveSheet().getName() === ws){
var currentDate = new Date();
//e.source.getActiveSheet().getRange("C1").setValue(currentDate);   //1
if(e.source.getActiveSheet().getRange("C5").getValue() == ""){
e.source.getActiveSheet().getRange("C5").setValue(currentDate);
} //End IF check column, row, worksheet
} //End function addTimestamp

if(col === targetColumn4 && row >= startRow4 && e.source.getActiveSheet().getName() === ws){
var currentDate = new Date();
//e.source.getActiveSheet().getRange("D1").setValue(currentDate);    //2
if(e.source.getActiveSheet().getRange("D5").getValue() == ""){
e.source.getActiveSheet().getRange("D5").setValue(currentDate);
} //End IF check column, row, worksheet
} //End function addTimestamp

if(col === targetColumn5 && row >= startRow5 && e.source.getActiveSheet().getName() === ws){
var currentDate = new Date();
//e.source.getActiveSheet().getRange("E1").setValue(currentDate);    //2
if(e.source.getActiveSheet().getRange("E5").getValue() == ""){
e.source.getActiveSheet().getRange("E5").setValue(currentDate);
} //End IF check column, row, worksheet
} //End function addTimestamp

if(col === targetColumn6 && row >= startRow6 && e.source.getActiveSheet().getName() === ws){
var currentDate = new Date();
//e.source.getActiveSheet().getRange("F1").setValue(currentDate);    //3
if(e.source.getActiveSheet().getRange("F5").getValue() == ""){
e.source.getActiveSheet().getRange("F5").setValue(currentDate);
} //End IF check column, row, worksheet
} //End function addTimestamp

if(col === targetColumn7 && row >= startRow7 && e.source.getActiveSheet().getName() === ws){
var currentDate = new Date();
//e.source.getActiveSheet().getRange("G1").setValue(currentDate);    //4
if(e.source.getActiveSheet().getRange("G5").getValue() == ""){
e.source.getActiveSheet().getRange("G5").setValue(currentDate);
} //End IF check column, row, worksheet
} //End function addTimestamp

if(col === targetColumn8 && row >= startRow8 && e.source.getActiveSheet().getName() === ws){
var currentDate = new Date();
//e.source.getActiveSheet().getRange("H1").setValue(currentDate);    //5
if(e.source.getActiveSheet().getRange("H5").getValue() == ""){
e.source.getActiveSheet().getRange("H5").setValue(currentDate);
} //End IF check column, row, worksheet
} //End function addTimestamp


if(col === targetColumn9 && row >= startRow9 && e.source.getActiveSheet().getName() === ws){
var currentDate = new Date();
//e.source.getActiveSheet().getRange("I1").setValue(currentDate);   //6
if(e.source.getActiveSheet().getRange("I5").getValue() == ""){
e.source.getActiveSheet().getRange("I5").setValue(currentDate);
} //End IF check column, row, worksheet
} //End function addTimestamp
//////////////////////////////////////////////////////////////////////////////////////////////
if(col === targetColumn10 && row >= startRow10 && e.source.getActiveSheet().getName() === ws){
var currentDate = new Date();
//e.source.getActiveSheet().getRange("J1").setValue(currentDate);   //7
if(e.source.getActiveSheet().getRange("J5").getValue() == ""){
e.source.getActiveSheet().getRange("J5").setValue(currentDate);
} //End IF check column, row, worksheet
} //End function addTimestamp


if(col === targetColumn10 && row >= startRow10 && e.source.getActiveSheet().getName() === ws){
var currentDate = new Date();
//e.source.getActiveSheet().getRange("K1").setValue(currentDate);   //8
if(e.source.getActiveSheet().getRange("K5").getValue() == ""){
e.source.getActiveSheet().getRange("K5").setValue(currentDate);
} //End IF check column, row, worksheet
} //End function addTimestamp

if(col === targetColumn11 && row >= startRow11 && e.source.getActiveSheet().getName() === ws){
var currentDate = new Date();
//e.source.getActiveSheet().getRange("L1").setValue(currentDate);   //9
if(e.source.getActiveSheet().getRange("L5").getValue() == ""){
e.source.getActiveSheet().getRange("L5").setValue(currentDate);
} //End IF check column, row, worksheet
} //End function addTimestamp


if(col === targetColumn12 && row >= startRow12 && e.source.getActiveSheet().getName() === ws){
var currentDate = new Date();
//e.source.getActiveSheet().getRange("M1").setValue(currentDate);   //10
if(e.source.getActiveSheet().getRange("M5").getValue() == ""){
e.source.getActiveSheet().getRange("M5").setValue(currentDate);
} //End IF check column, row, worksheet
} //End function addTimestamp

if(col === targetColumn13 && row >= startRow13 && e.source.getActiveSheet().getName() === ws){
var currentDate = new Date();
//e.source.getActiveSheet().getRange("N1").setValue(currentDate);   //11
if(e.source.getActiveSheet().getRange("N5").getValue() == ""){
e.source.getActiveSheet().getRange("N5").setValue(currentDate);
} //End IF check column, row, worksheet
} //End function addTimestamp

if(col === targetColumn14 && row >= startRow14 && e.source.getActiveSheet().getName() === ws){
var currentDate = new Date();
//e.source.getActiveSheet().getRange("N1").setValue(currentDate);   //12
if(e.source.getActiveSheet().getRange("N5").getValue() == ""){
e.source.getActiveSheet().getRange("N5").setValue(currentDate);
} //End IF check column, row, worksheet
} //End function addTimestamp


if(col === targetColumn15 && row >= startRow15 && e.source.getActiveSheet().getName() === ws){
var currentDate = new Date();
//e.source.getActiveSheet().getRange("O1").setValue(currentDate);  //13
if(e.source.getActiveSheet().getRange("O5").getValue() == ""){
e.source.getActiveSheet().getRange("O5").setValue(currentDate);
} //End IF check column, row, worksheet
} //End function addTimestamp
///////////////////////////////////////////////////////////////////////////////////////////////
if(col === targetColumn17 && row >= startRow17 && e.source.getActiveSheet().getName() === ws){
var currentDate = new Date();
//e.source.getActiveSheet().getRange("Q1").setValue(currentDate);   //14
if(e.source.getActiveSheet().getRange("Q5").getValue() == ""){
e.source.getActiveSheet().getRange("Q5").setValue(currentDate);
} //End IF check column, row, worksheet
} //End function addTimestamp

if(col === targetColumn18 && row >= startRow18 && e.source.getActiveSheet().getName() === ws){
var currentDate = new Date();
//e.source.getActiveSheet().getRange("S1").setValue(currentDate);   // 15
if(e.source.getActiveSheet().getRange("S5").getValue() == ""){
e.source.getActiveSheet().getRange("S5").setValue(currentDate);
} //End IF check column, row, worksheet
} //End function addTimestamp

if(col === targetColumn19 && row >= startRow19 && e.source.getActiveSheet().getName() === ws){
var currentDate = new Date();
//e.source.getActiveSheet().getRange("U1").setValue(currentDate);   // 16
if(e.source.getActiveSheet().getRange("U5").getValue() == ""){
e.source.getActiveSheet().getRange("U5").setValue(currentDate);
} //End IF check column, row, worksheet
} //End function addTimestamp

}