description: You are given a sequence a_1, a_2, ..., a_n consisting of n pairwise distinct positive integers.
  
  Find \left⌊ \frac n 2 \right⌋ different pairs of integers x and y such that: 
  
    * x ≠ y; 
    * x and y appear in a; 
    * x~mod~y doesn't appear in a. 
  
  
  
  Note that some x or y can belong to multiple pairs.
  
  ⌊ x ⌋ denotes the floor function — the largest integer less than or equal to x. x~mod~y denotes the remainder from dividing x by y.
  
  If there are multiple solutions, print any of them. It can be shown that at least one solution always exists.
  
  Input
  
  The first line contains a single integer t (1 ≤ t ≤ 10^4) — the number of testcases.
  
  The first line of each testcase contains a single integer n (2 ≤ n ≤ 2 ⋅ 10^5) — the length of the sequence.
  
  The second line of each testcase contains n integers a_1, a_2, ..., a_n (1 ≤ a_i ≤ 10^6).
  
  All numbers in the sequence are pairwise distinct. The sum of n over all testcases doesn't exceed 2 ⋅ 10^5.
  
  Output
  
  The answer for each testcase should contain \left⌊ \frac n 2 \right⌋ different pairs of integers x and y such that x ≠ y, x and y appear in a and x~mod~y doesn't appear in a. Print the pairs one after another.
  
  You can print the pairs in any order. However, the order of numbers in the pair should be exactly such that the first number is x and the second number is y. All pairs should be pairwise distinct.
  
  If there are multiple solutions, print any of them.
  
  Example
  
  Input
  
  
  4
  2
  1 4
  4
  2 8 3 4
  5
  3 8 5 9 7
  6
  2 7 5 3 4 8
  
  
  Output
  
  
  4 1
  8 2
  8 4
  9 5
  7 5
  8 7
  4 3
  5 2
  
  Note
  
  In the first testcase there are only two pairs: (1, 4) and (4, 1). \left⌊ \frac 2 2 \right⌋=1, so we have to find one pair. 1~mod~4=1, and 1 appears in a, so that pair is invalid. Thus, the only possible answer is a pair (4, 1).
  
  In the second testcase, we chose pairs 8~mod~2=0 and 8~mod~4=0. 0 doesn't appear in a, so that answer is valid. There are multiple possible answers for that testcase.
  
  In the third testcase, the chosen pairs are 9~mod~5=4 and 7~mod~5=2. Neither 4, nor 2, appears in a, so that answer is valid.
solution: import java.util.*;
  import java.lang.*;
  import java.io.*;
  
  public class Main
  {
      static long mod = (int)1e9+7;
      // static PrintWriter out = new PrintWriter(new BufferedOutputStream(System.out));
  	public static void main (String[] args) throws java.lang.Exception
  	{
  		FastReader sc =new FastReader();
  		
  	    int t=sc.nextInt();
  	    
  	   // int t=1;
  	    
  	    while(t-->0)
  	    {
  	        int n = sc.nextInt();
  	        int arr[] = sc.readArray(n);
  	        
  	        radixSort2(arr);
  	        int count = 0;
  	        
  	            for(int i=1;i<n;i++)
  	            {
  	                if(count < n/2)
  	                {
  	                    System.out.println(arr[i]+" "+arr[0]);
  	                    count++;
  	                }
  	                else
  	                {
  	                    break;
  	                }
  	            }
  	        
  	    }
  	    
  	}
  	
  	
  	
  	
  	static class FastReader {
          BufferedReader br;
          StringTokenizer st;
   
          public FastReader()
          {
              br = new BufferedReader(
                  new InputStreamReader(System.in));
          }
   
          String next()
          {
              while (st == null || !st.hasMoreElements()) {
                  try {
                      st = new StringTokenizer(br.readLine());
                  }
                  catch (IOException e) {
                      e.printStackTrace();
                  }
              }
              return st.nextToken();
          }
   
          int nextInt() { return Integer.parseInt(next()); }
   
          long nextLong() { return Long.parseLong(next()); }
   
          double nextDouble()
          {
              return Double.parseDouble(next());
          }
          
          float nextFloat()
          {
              return Float.parseFloat(next());
          }
   
          String nextLine()
          {
              String str = "";
              try {
                  str = br.readLine();
              }
              catch (IOException e) {
                  e.printStackTrace();
              }
              return str;
          }
          
          int[] readArray(int n) {
  			int[] a=new int[n];
  			for (int i=0; i<n; i++) a[i]=nextInt();
  			return a;
  		}
  		
  		long[] readArrayLong(int n) {
  			long[] a=new long[n];
  			for (int i=0; i<n; i++) a[i]=nextLong();
  			return a;
  		}
  		
      }
      
      
      
      public static int[] radixSort2(int[] a)
  	{
  		int n = a.length;
  		int[] c0 = new int[0x101];
  		int[] c1 = new int[0x101];
  		int[] c2 = new int[0x101];
  		int[] c3 = new int[0x101];
  		for(int v : a) {
  			c0[(v&0xff)+1]++;
  			c1[(v>>>8&0xff)+1]++;
  			c2[(v>>>16&0xff)+1]++;
  			c3[(v>>>24^0x80)+1]++;
  		}
  		for(int i = 0;i < 0xff;i++) {
  			c0[i+1] += c0[i];
  			c1[i+1] += c1[i];
  			c2[i+1] += c2[i];
  			c3[i+1] += c3[i];
  		}
  		int[] t = new int[n];
  		for(int v : a)t[c0[v&0xff]++] = v;
  		for(int v : t)a[c1[v>>>8&0xff]++] = v;
  		for(int v : a)t[c2[v>>>16&0xff]++] = v;
  		for(int v : t)a[c3[v>>>24^0x80]++] = v;
  		return a;
  	}
  	
  	static void reverse_sorted(int[] arr)
  	{
  	    ArrayList<Integer> list = new ArrayList<>();
  	    for(int i=0;i<arr.length;i++)
  	    {
  	        list.add(arr[i]);
  	    }
  	    Collections.sort(list , Collections.reverseOrder());
  	    for(int i=0;i<arr.length;i++)
  	    {
  	        arr[i] = list.get(i);
  	    }
  	}
  	
  	static int LowerBound(int a[], int x) { // x is the target value or key
          int l=-1,r=a.length;
          while(l+1<r) {
              int m=(l+r)>>>1;
              if(a[m]>=x) r=m;
              else l=m;
          }
          return r;
      }
      
      static int UpperBound(ArrayList<Integer> list, int x) {// x is the key or target value
          int l=-1,r=list.size();
          while(l+1<r) {
              int m=(l+r)>>>1;
              if(list.get(m)<=x) l=m;
              else r=m;
          }
          return l+1;
      }
      
      public static HashMap<Integer, Integer> sortByValue(HashMap<Integer, Integer> hm)
      {
          // Create a list from elements of HashMap
          List<Map.Entry<Integer, Integer> > list =
                 new LinkedList<Map.Entry<Integer, Integer> >(hm.entrySet());
   
          // Sort the list
          Collections.sort(list, new Comparator<Map.Entry<Integer, Integer> >() {
              public int compare(Map.Entry<Integer, Integer> o1,
                                 Map.Entry<Integer, Integer> o2)
              {
                  return (o1.getValue()).compareTo(o2.getValue());
              }
          });
           
          // put data from sorted list to hashmap
          HashMap<Integer, Integer> temp = new LinkedHashMap<Integer, Integer>();
          for (Map.Entry<Integer, Integer> aa : list) {
              temp.put(aa.getKey(), aa.getValue());
          }
          return temp;
      }
      
      static class Queue_Pair implements Comparable<Queue_Pair> {
  		int first , second;
  		public Queue_Pair(int first, int second) {
  			this.first=first;
  			this.second=second;
  		}
  		public int compareTo(Queue_Pair o) {
  			return Integer.compare(o.first, first);
  		}
  	}
      
      static void leftRotate(int arr[], int d, int n)
      {
          for (int i = 0; i < d; i++)
              leftRotatebyOne(arr, n);
      }
   
      static void leftRotatebyOne(int arr[], int n)
      {
          int i, temp;
          temp = arr[0];
          for (i = 0; i < n - 1; i++)
              arr[i] = arr[i + 1];
          arr[n-1] = temp;
          
      }
      
      static boolean isPalindrome(String str)
      {
   
          // Pointers pointing to the beginning
          // and the end of the string
          int i = 0, j = str.length() - 1;
   
          // While there are characters to compare
          while (i < j) {
   
              // If there is a mismatch
              if (str.charAt(i) != str.charAt(j))
                  return false;
   
              // Increment first pointer and
              // decrement the other
              i++;
              j--;
          }
   
          // Given string is a palindrome
          return true;
      }
      
      static boolean palindrome_array(char arr[], int n)
      {
          // Initialise flag to zero.
          int flag = 0;
   
          // Loop till array size n/2.
          for (int i = 0; i <= n / 2 && n != 0; i++) {
   
              // Check if first and last element are different
              // Then set flag to 1.
              if (arr[i] != arr[n - i - 1]) {
                  flag = 1;
                  break;
              }
          }
   
          // If flag is set then print Not Palindrome
          // else print Palindrome.
          if (flag == 1)
              return false;
          else
              return true;
      }
      
  	static boolean allElementsEqual(int[] arr,int n)
  	{
  	    int z=0;
  	        for(int i=0;i<n-1;i++)
  		    {
  		        if(arr[i]==arr[i+1])
  		        {
  		            z++;
  		        }
  		    }
  		    if(z==n-1)
  		    {
  		        return true;
  		    }
  		    else
  		    {
  		        return false;
  		    }
  		    
  	}
  	
  	static boolean allElementsDistinct(int[] arr,int n)
  	{
  	    int z=0;
  	        for(int i=0;i<n-1;i++)
  		    {
  		        if(arr[i]!=arr[i+1])
  		        {
  		            z++;
  		        }
  		    }
  		    if(z==n-1)
  		    {
  		        return true;
  		    }
  		    else
  		    {
  		        return false;
  		    }
  		    
  		    
  	}
  	
  	public static void reverse(int[] array)
      {
    
          // Length of the array
          int n = array.length;
    
          // Swaping the first half elements with last half
          // elements
          for (int i = 0; i < n / 2; i++) {
    
              // Storing the first half elements temporarily
              int temp = array[i];
    
              // Assigning the first half to the last half
              array[i] = array[n - i - 1];
    
              // Assigning the last half to the first half
              array[n - i - 1] = temp;
          }
      }
      
      public static void reverse_Long(long[] array)
      {
    
          // Length of the array
          int n = array.length;
    
          // Swaping the first half elements with last half
          // elements
          for (int i = 0; i < n / 2; i++) {
    
              // Storing the first half elements temporarily
              long temp = array[i];
    
              // Assigning the first half to the last half
              array[i] = array[n - i - 1];
    
              // Assigning the last half to the first half
              array[n - i - 1] = temp;
          }
      }
  	
  	static boolean isSorted(int[] a)
      {
          for (int i = 0; i < a.length - 1; i++)
          {
              if (a[i] > a[i + 1]) {
                  return false;
              }
          }
   
          return true;
      }
      
      
      
      static boolean isReverseSorted(int[] a)
      {
          for (int i = 0; i < a.length - 1; i++)
          {
              if (a[i] < a[i + 1]) {
                  return false;
              }
          }
   
          return true;
      }
      
      static int[] rearrangeEvenAndOdd(int arr[], int n)
      {
          ArrayList<Integer> list = new ArrayList<>();
  		    
  		    for(int i=0;i<n;i++)
  		    {
  		        if(arr[i]%2==0)
  		        {
  		            list.add(arr[i]);
  		        }
  		    }
  		    
  		    for(int i=0;i<n;i++)
  		    {
  		        if(arr[i]%2!=0)
  		        {
  		            list.add(arr[i]);
  		        }
  		    }
  		    int len = list.size();
  		    int[] array = list.stream().mapToInt(i->i).toArray();
  		    return array;
      }
      
      static long[] rearrangeEvenAndOddLong(long arr[], int n)
      {
          ArrayList<Long> list = new ArrayList<>();
  		    
  		    for(int i=0;i<n;i++)
  		    {
  		        if(arr[i]%2==0)
  		        {
  		            list.add(arr[i]);
  		        }
  		    }
  		    
  		    for(int i=0;i<n;i++)
  		    {
  		        if(arr[i]%2!=0)
  		        {
  		            list.add(arr[i]);
  		        }
  		    }
  		    int len = list.size();
  		    long[] array = list.stream().mapToLong(i->i).toArray();
  		    return array;
      }
  	
  	
      
      static boolean isPrime(long n)
      {
   
          // Check if number is less than
          // equal to 1
          if (n <= 1)
              return false;
   
          // Check if number is 2
          else if (n == 2)
              return true;
   
          // Check if n is a multiple of 2
          else if (n % 2 == 0)
              return false;
   
          // If not, then just check the odds
          for (long i = 3; i <= Math.sqrt(n); i += 2)
          {
              if (n % i == 0)
                  return false;
          }
          return true;
      }
      
      static long getSum(long n)
      {    
          long sum = 0;
            
          while (n != 0)
          {
              sum = sum + n % 10;
              n = n/10;
          }
        
      return sum;
      }
      
      static int gcd(int a, int b)
      {
        if (b == 0)
          return a;
        return gcd(b, a % b);
      }
       
      static long gcdLong(long a, long b)
      {
          if (b == 0)
          return a;
        return gcdLong(b, a % b);
      }
      
      static void swap(int i, int j)
      {
          int temp = i;
          i = j;
          j = temp;
      }
  	
  	static int countDigit(int n)
      {
          return (int)Math.floor(Math.log10(n) + 1);
      }
  	
  }
  
  class Pair
  {
      int first;
      int second;
      Pair(int first , int second)
      {
          this.first = first;
          this.second = second;
      }
  }
  