JAva:単語置換:1つの文字列の一部の単語を特別な語彙で置換する

package com.ethjava;

import java.util.ArrayList;
import java.util.Scanner;

public class wordswap {

    public static void main(String[] args) {
        //     ， Arraylist    word    ，      ，       
        Scanner sc = new Scanner(System.in);
        ArrayList arrList = new ArrayList();

        while(sc.hasNext()) {
            String str = sc.nextLine();
            String[] word=str.split(" ");
            for(int i=0;i 
  
You want someone to help you
You
I
  
YOUをIに き える
  
  
I want someone to help you