救命，老師快救我。阿阿阿阿阿阿阿阿阿阿

import java.io.*;
import java.util.*;
public class jva110
{
public static void main(String arg[])
{
//取得出題數量
int userItemCoount = arg.length / 2;
//是否為使用者出題(自由出題)
Boolean isUserItem = (userItemCoount > 0);
//宣告題目陣列
String itemQue[];
String itemAns[];
//判斷是否是自由出題
if(isUserItem)
{
//是自由出題
//建立陣列
itemQue = new String[userItemCoount];
itemAns = new String[userItemCoount];
//寫入題目
for(int i=0;i<arg.length;i+=2)
{
itemQue[i/2] = arg[i];
itemAns[i/2] = arg[i+1];
}
}else{
//是預設題目
itemQue = new String[]{"電腦","資料庫","語法","學校","假期"};
itemAns = new String[]{"computer","database","syntax","school","Vocation"};
}
//紀錄開始時間
long startTime = new Date().getTime();
//顯示資訊
System.out.println("請將題目的中文字彙翻譯成英文單字!");
System.out.println("輸入英文單字答案後請按Enter鍵:\n");
//輸入擷取物件
Scanner scanner =new Scanner(System.in);
//宣告答對題目數變數
int Right=0;
//開始出題
for(int i=0;i<itemQue.length;i++)
{
System.out.println("第" + (i+1) +"題__ " + itemQue[i]);
String useInput = scanner.next();
String ans = itemAns[i].toLowerCass();
useInput = useInput.toLowerCass();
if(useInput.equals(ans))
{
System.out.println("答對了！");
Right++;
}else{
System.out.println("答錯了！");
System.out.println("正確答案是" + itemAns[i]+"\n");
}
}
//結算時間
long endTime = new Date().getTime();
long useTime = (endTime-startTime)/1000;
System.out.println("你使用了" + useTime + "秒，在" + itemQue.length + "題中答對了" + Right + "題");
}
}

複製代碼

老師，為甚麼一直有兩個錯誤訊息

錯誤訊息如下
jva110.java:54: error: cannot find symbol/ T( w+ {6 N  W: L* u$ r  T
                     String ans = itemAns.toLowerCass();
' c0 _2 H5 P: H: g                                              ^7 J0 w( M& ^0 F: d' R
  symbol: method toLowerCass()$ r- P2 W3 _/ _+ S( B& l
  location: class String
& ]# @( t3 [% t7 Ejva110.java:55: error: cannot find symbol
/ u, F6 f" b: W  J* M" @) P0 {                      useInput = useInput.toLowerCass();( E9 l/ S5 I! M5 u! s
                                       ^# B5 E, Z+ s5 l$ |
  symbol: method toLowerCass()
! y; V) w! k/ s4 h  location: variable useInput of type String
1 d% P  S, B& E  X9 A& v2 I2 errors