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.io.*;
  import java.math.*;
  import java.lang.*;
  
  public class b {
      
      // static int mod = 998244353;
      static int mod = 1000000007;
  
      public static class Reader {
          final private int BUFFER_SIZE = 1 << 16;
          private DataInputStream din;
          private byte[] buffer;
          private int bufferPointer, bytesRead;
   
          public Reader()
          {
              din = new DataInputStream(System.in);
              buffer = new byte[BUFFER_SIZE];
              bufferPointer = bytesRead = 0;
          }
   
          public Reader(String file_name) throws IOException
          {
              din = new DataInputStream(
                  new FileInputStream(file_name));
              buffer = new byte[BUFFER_SIZE];
              bufferPointer = bytesRead = 0;
          }
   
          public String readLine() throws IOException
          {
              byte[] buf = new byte[64]; // line length
              int cnt = 0, c;
              while ((c = read()) != -1) {
                  if (c == '\n') {
                      if (cnt != 0) {
                          break;
                      }
                      else {
                          continue;
                      }
                  }
                  buf[cnt++] = (byte)c;
              }
              return new String(buf, 0, cnt);
          }
   
          public int nextInt() throws IOException
          {
              int ret = 0;
              byte c = read();
              while (c <= ' ') {
                  c = read();
              }
              boolean neg = (c == '-');
              if (neg)
                  c = read();
              do {
                  ret = ret * 10 + c - '0';
              } while ((c = read()) >= '0' && c <= '9');
   
              if (neg)
                  return -ret;
              return ret;
          }
   
          public long nextLong() throws IOException
          {
              long ret = 0;
              byte c = read();
              while (c <= ' ')
                  c = read();
              boolean neg = (c == '-');
              if (neg)
                  c = read();
              do {
                  ret = ret * 10 + c - '0';
              } while ((c = read()) >= '0' && c <= '9');
              if (neg)
                  return -ret;
              return ret;
          }
   
          public double nextDouble() throws IOException
          {
              double ret = 0, div = 1;
              byte c = read();
              while (c <= ' ')
                  c = read();
              boolean neg = (c == '-');
              if (neg)
                  c = read();
   
              do {
                  ret = ret * 10 + c - '0';
              } while ((c = read()) >= '0' && c <= '9');
   
              if (c == '.') {
                  while ((c = read()) >= '0' && c <= '9') {
                      ret += (c - '0') / (div *= 10);
                  }
              }
   
              if (neg)
                  return -ret;
              return ret;
          }
   
          private void fillBuffer() throws IOException
          {
              bytesRead = din.read(buffer, bufferPointer = 0,
                                   BUFFER_SIZE);
              if (bytesRead == -1)
                  buffer[0] = -1;
          }
   
          private byte read() throws IOException
          {
              if (bufferPointer == bytesRead)
                  fillBuffer();
              return buffer[bufferPointer++];
          }
   
          public void close() throws IOException
          {
              if (din == null)
                  return;
              din.close();
          }
      }
  
      public static void main(String[] args) throws Exception {
          Reader scn = new Reader();
          PrintWriter pw = new PrintWriter(System.out);
          int t = scn.nextInt();
          outer : while(t-->0){
              int n = scn.nextInt();
              int[] arr = new int[n];
              for(int i=0; i<n; i++){
                  arr[i] = scn.nextInt();
              }
              sort(arr);
              int min = arr[0];
              int pairs = n/2;
              for(int i=1; i<=pairs; i++){
                  pw.println(arr[i] + " " + min);
              }
          }
          pw.close();
      }
  
      public static class Pair{
          int x;
          int y;
  
          Pair(int x, int y){
              this.x = x;
              this.y = y;
          }
      }
  
      private static void sort(int[] arr) {
          List<Integer> list = new ArrayList<>();
          for (int i=0; i<arr.length; i++){
              list.add(arr[i]);
          }
          Collections.sort(list); // collections.sort uses nlogn in backend
          for (int i = 0; i < arr.length; i++){
              arr[i] = list.get(i);
          }
      }
  
      private static void sort(long[] arr) {
          List<Long> list = new ArrayList<>();
          for(int i=0; i<arr.length; i++){
              list.add(arr[i]);
          }
          Collections.sort(list); // collections.sort uses nlogn in backend
          for (int i = 0; i < arr.length; i++){
              arr[i] = list.get(i);
          }
      }
  
      // private static void sort(Pair[] arr) {
      //     List<Pair> list = new ArrayList<>();
      //     for(int i=0; i<arr.length; i++){
      //         list.add(arr[i]);
      //     }
      //     Collections.sort(list); // collections.sort uses nlogn in backend
      //     for (int i = 0; i < arr.length; i++){
      //         arr[i] = list.get(i);
      //     }
      // }
  
      private static void reverseSort(int[] arr){
          List<Integer> list = new ArrayList<>();
          for (int i=0; i<arr.length; i++){
              list.add(arr[i]);
          }
          Collections.sort(list, Collections.reverseOrder()); // collections.sort uses nlogn in backend
          for (int i = 0; i < arr.length; i++){
              arr[i] = list.get(i);
          }
      }
  
      private static void reverseSort(long[] arr){
          List<Long> list = new ArrayList<>();
          for (int i=0; i<arr.length; i++){
              list.add(arr[i]);
          }
          Collections.sort(list, Collections.reverseOrder()); // collections.sort uses nlogn in backend
          for (int i = 0; i < arr.length; i++){
              arr[i] = list.get(i);
          }
      }
  
      private static void reverseSort(ArrayList<Integer> list){
          Collections.sort(list, Collections.reverseOrder());
      }
  
      private static int lowerBound(int[] arr, int x){
          int n = arr.length, si = 0, ei = n - 1;
          while(si <= ei){
              int mid = si + (ei - si)/2;
              if(arr[mid] == x){
                  if(mid-1 >= 0 && arr[mid-1] == arr[mid]){
                      ei = mid-1;
                  }else{
                      return mid;
                  }
              }else if(arr[mid] > x){
                  ei = mid - 1; 
              }else{
                  si = mid+1;
              }
          }
          return si; 
      }
  
      private static int upperBound(int[] arr, int x){
          int n = arr.length, si = 0, ei = n - 1;
          while(si <= ei){
              int mid = si + (ei - si)/2;
              if(arr[mid] == x){
                  if(mid+1 < n && arr[mid+1] == arr[mid]){
                      si = mid+1;
                  }else{
                      return mid + 1;
                  }
              }else if(arr[mid] > x){
                  ei = mid - 1; 
              }else{
                  si = mid+1;
              }
          }
          return si; 
      }
  
      private static int upperBound(ArrayList<Integer> list, int x){
          int n = list.size(), si = 0, ei = n - 1;
          while(si <= ei){
              int mid = si + (ei - si)/2;
              if(list.get(mid) == x){
                  if(mid+1 < n && list.get(mid+1) == list.get(mid)){
                      si = mid+1;
                  }else{
                      return mid + 1;
                  }
              }else if(list.get(mid) > x){
                  ei = mid - 1; 
              }else{
                  si = mid+1;
              }
          }
          return si; 
      }
  
      // (x^y)%p in O(logy)
      private static long power(long x, long y){
          long res = 1; 
          x = x % mod;
          while(y > 0){
              if ((y & 1) == 1){
                  res = (res * x) % mod;
              }
              y = y >> 1; 
              x = (x * x) % mod;
          }
          return res;
      }
  
      public static boolean nextPermutation(int[] arr) {
          if(arr == null || arr.length <= 1){
              return false;
          }
          
          int last = arr.length-2;
          while(last >= 0){
              if(arr[last] < arr[last+1]){
                  break;
              }
              last--;
          }
  
          if (last < 0){
                return false;
          }
          
          if(last >= 0){
              int nextGreater = arr.length-1;
              for(int i=arr.length-1; i>last; i--){
                  if(arr[i] > arr[last]){
                      nextGreater = i;
                      break;
                  }
              }
              swap(arr, last, nextGreater);
          }
          
          reverse(arr, last+1, arr.length-1);
          return true;
      }
      
      private static void swap(int[] arr, int i, int j){
          int temp = arr[i];
          arr[i] = arr[j];
          arr[j] = temp;
      }
      
      private static void reverse(int[] arr, int i, int j){
          while(i < j){
              swap(arr, i++, j--);
          }
      }
  
      private static String reverseStr(String s){
          StringBuilder sb = new StringBuilder(s);
          return sb.reverse().toString();
      }
  
      // TC- O(logmax(a,b))
      private static int gcd(int a, int b) {
          if(a == 0){
              return b;
          }
          return gcd(b%a, a);
      }
  
      private static long gcd(long a, long b) {
          if(a == 0L){
              return b;
          }
          return gcd(b%a, a);
      }
  
      private static long lcm(long a, long b) {
          return a / gcd(a, b) * b;
      }
  
      // TC- O(logmax(a,b))
      private static int lcm(int a, int b) {
          return a / gcd(a, b) * b;
      }
  
      private static long inv(long x){
          return power(x, mod - 2);
      }
  
      private static long summation(long n){
          return (n * (n + 1L)) >> 1;
      } 
  }