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.io.*;
  import java.util.*;
  
  
  public class Practice
  {
  //	static final long mod=7420738134811L;
  	static int mod=1000000007;
  	static final int size=501;
  	static FastReader sc=new FastReader(System.in);
  //	static Reader sc=new Reader();
  //	static Scanner sc=new Scanner(System.in);
  	static  PrintWriter out=new PrintWriter(System.out);
  	static long[] factorialNumInverse;
  	static long[] naturalNumInverse;	
  	static int[] sp;
  	static long[] fact;
  	static ArrayList<Integer> pr;
  	public static void main(String[] args) throws IOException, CloneNotSupportedException
  	{
  //		System.setIn(new FileInputStream("input.txt"));
  //		System.setOut(new PrintStream("output.txt"));
  //		factorial(mod);
  //		InverseofNumber(mod);
  //		InverseofFactorial(mod);
  //		make_seive();
  		int t=1;
  		t=sc.nextInt();
  		int i=1;
  		for(i=1;i<=t;i++)
  			solve(i);
  		out.close();
  		out.flush();
  //		System.out.flush();
  //		System.exit(0);
  	}
  	static void solve(int CASENO) throws IOException, CloneNotSupportedException
  	{
  		int n=sc.nextInt();
  		int arr[]=new int[n];
  		for(int i=0;i<n;i++)
  			arr[i]=sc.nextInt();
  		arraySort(arr);
  		for(int i=1;i<=n/2;i++)
  			out.println(arr[i]+" "+arr[0]);
  	}
  	static class Pair implements Cloneable, Comparable<Pair>
  	{
  		int x,y;
  		Pair(int a,int b)
  		{
  			this.x=a;
  			this.y=b;
  		}
  		@Override
  		public boolean equals(Object obj) 
  		{
  			if(obj instanceof  Pair)
  			{
  				Pair p=(Pair)obj;
  				return p.x==this.x && p.y==this.y;
  			}
  			return false;
  		}
  		@Override
  		public int hashCode() 
  		{
  			return Math.abs(x)+500*Math.abs(y);
  		}
  		@Override
  		public String toString() 
  		{
  			return "("+x+" "+y+")";
  		}
  		@Override
  		protected Pair clone() throws CloneNotSupportedException {
  			return new Pair(this.x,this.y);
  		}
  		@Override
  		public int compareTo(Pair a) 
  		{
  			long t=(a.x-this.x);
  			if(t!=0)
  				return t>0?1:-1;
  			else
  				return (int)(this.y-a.y);
  		}
  		public void swap()
  		{
  			this.y=this.y+this.x;
  			this.x=this.y-this.x;
  			this.y=this.y-this.x;			
  		}
  	}
  	static class Tuple implements Cloneable, Comparable<Tuple>
  	{
  		int x,y,z;
  		Tuple(int a,int b,int c)
  		{
  			this.x=a;
  			this.y=b;
  			this.z=c;
  		}
  		public boolean equals(Object obj) 
  		{
  			if(obj instanceof  Tuple)
  			{
  				Tuple p=(Tuple)obj;
  				return p.x==this.x && p.y==this.y && p.z==this.z;
  			}
  			return false;
  		}
  		@Override
  		public int hashCode() 
  		{
  			return (this.x+501*this.y);
  		}
  		@Override
  		public String toString() 
  		{
  			return "("+x+","+y+","+z+")";
  		}
  		@Override
  		protected Tuple clone() throws CloneNotSupportedException {
  			return new Tuple(this.x,this.y,this.z);
  		}
  		@Override
  		public int compareTo(Tuple a) 
  		{
  			int x=this.z-a.z;
  			if(x!=0)
  				return x;
  			int X= this.x-a.x;
  			if(X!=0)
  				return X;
  			return a.y-this.y;
  		}
  	}
  	static void arraySort(int arr[])
  	{
  		ArrayList<Integer> a=new ArrayList<Integer>();
  		for (int i = 0; i < arr.length; i++) {
  			a.add(arr[i]);
  		}
  		Collections.sort(a);
  		for (int i = 0; i < arr.length; i++) {
  			arr[i]=a.get(i);
  		}
  	}
  	static void arraySort(long arr[])
  	{
  		ArrayList<Long> a=new ArrayList<Long>();
  		for (int i = 0; i < arr.length; i++) {
  			a.add(arr[i]);
  		}
  		Collections.sort(a);
  		for (int i = 0; i < arr.length; i++) {
  			arr[i]=a.get(i);
  		}
  	}
  	static HashSet<Integer> primeFactors(int n)
  	{
  		HashSet<Integer> ans=new HashSet<Integer>();
  		if(n%2==0)
  		{
  			ans.add(2);
  			while((n&1)==0)
  				n=n>>1;
  		}
  		for(int i=3;i*i<=n;i+=2)
  		{
  			if(n%i==0)
  			{
  				ans.add(i);
  				while(n%i==0)
  					n=n/i;
  			}
  		}
  		if(n!=1)
  			ans.add(n);
  		return ans;
  	}
  	static void make_seive()
  	{
  		sp=new int[size];
  		pr=new ArrayList<Integer>();
  		for (int i=2; i<size; ++i) {
  		    if (sp[i] == 0) {
  		        sp[i] = i;
  		        pr.add(i);
  		    }
  		    for (int j=0; j<(int)pr.size() && pr.get(j)<=sp[i] && i*pr.get(j)<size; ++j)
  		        sp[i * pr.get(j)] = pr.get(j);
  		}
  	}
  	public static void InverseofNumber(int p)
  	{
  		naturalNumInverse=new long[size];
  	    naturalNumInverse[0] = naturalNumInverse[1] = 1;
  	    for(int i = 2; i < size; i++)
  	        naturalNumInverse[i] = naturalNumInverse[p % i] * (long)(p - p / i) % p;
  	}
  	// Function to precompute inverse of factorials
  	public static void InverseofFactorial(int p)
  	{
  		factorialNumInverse=new long[size];
  	    factorialNumInverse[0] = factorialNumInverse[1] = 1;
  	    // pre-compute inverse of natural numbers
  	    for(int i = 2; i < size; i++)
  	        factorialNumInverse[i] = (naturalNumInverse[i] * factorialNumInverse[i - 1]) % p;
  	}
  	// Function to calculate factorial of 1 to 200001
  	public static void factorial(int p)
  	{
  		fact=new long[size];
  	    fact[0] = 1;
  	    for(int i = 1; i < size; i++)
  	        fact[i] = (fact[i - 1] * (long)i) % p;
  	}
  	 
  	// Function to return nCr % p in O(1) time
  	public static long Binomial(int N, int R)
  	{
  		if(R<0)
  			return 1;
  	    // n C r = n!*inverse(r!)*inverse((n-r)!)
  	    long ans = ((fact[N] * factorialNumInverse[R]) % mod * factorialNumInverse[N - R]) % mod;
  	    return ans;
  	}
  	static int findXOR(int x)	//from 0 to x
  	{
  		if(x<0)
  			return 0;
  		if(x%4==0)
  			return x;
  		if(x%4==1)
  			return 1;
  		if(x%4==2)
  			return x+1;
  		return 0;
  	}
  	static boolean isPrime(long x)
  	{
  		if(x==1)
  			return false;
  		if(x<=3)
  			return true;
  		if(x%2==0 || x%3==0)
  			return false;
  		for(int i=5;i<=Math.sqrt(x);i+=2)
  			if(x%i==0)
  				return false;
  		return true;
  	}
  	static long gcd(long a,long b)
  	{
  		return (b==0)?a:gcd(b,a%b);
  	}
  	static int gcd(int a,int b)
  	{
  		return (b==0)?a:gcd(b,a%b);
  	}
  	static class Node
  	{
  		int vertex,dis;
  		HashSet<Node> adj;
  		Node(int ver)
  		{
  			vertex=ver;
  			dis=-1;
  			adj=new HashSet<Node>();
  		}
  		@Override
  		public String toString() 
  		{
  			return vertex+" ";
  		}
  	}
  	static class Edge
  	{
  		Node to;
  		int cost;
  		Edge(Node t,int c)
  		{
  			this.to=t;
  			this.cost=c;
  		}
  		@Override
  		public String toString() {
  			return "("+to.vertex+","+cost+") ";
  		}
  	}
  	static long power(long x, long y)
  	  {
  		if(x<=0)
  			return 1;
  	    long res = 1; 
  	    x = x % mod; 
  	    if (x == 0)
  	      return 0; 
  	    while (y > 0)
  	    {
  	    	if ((y & 1) != 0)
  	    		res = (res * x) % mod;
  	    	
  	    	y = y >> 1; // y = y/2
  	    	x = (x * x) % mod;
  	    }
  	    return res%mod;
  	  }
  	static long binomialCoeff(long n, long k)
      {
  		if(n<k)
  			return 0;
          long res = 1;
          // Since C(n, k) = C(n, n-k)
          if (k > n - k)
              k = n - k;
   
          // Calculate value of
          // [n * (n-1) *---* (n-k+1)] / [k * (k-1) *----* 1]
          for (long i = 0; i < k; ++i) {
              res *= (n - i);
              res /= (i + 1);
          }
   
          return res;
      }
  	static class FastReader
  	{
          byte[] buf = new byte[2048];
          int index, total;
          InputStream in;
   
          FastReader(InputStream is) 
          {
              in = is;
          }
   
          int scan() throws IOException 
          {
              if (index >= total) {
                  index = 0;
                  total = in.read(buf);
                  if (total <= 0) {
                      return -1;
                  }
              }
              return buf[index++];
          }
   
          String next() throws IOException 
          {
              int c;
              for (c = scan(); c <= 32; c = scan());
              StringBuilder sb = new StringBuilder();
              for (; c > 32; c = scan()) {
                  sb.append((char) c);
              }
              return sb.toString();
          }
   
          int nextInt() throws IOException 
          {
              int c, val = 0;
              for (c = scan(); c <= 32; c = scan());
              boolean neg = c == '-';
              if (c == '-' || c == '+') {
                  c = scan();
              }
              for (; c >= '0' && c <= '9'; c = scan()) {
                  val = (val << 3) + (val << 1) + (c & 15);
              }
              return neg ? -val : val;
          }
   
          long nextLong() throws IOException 
          {
              int c;
              long val = 0;
              for (c = scan(); c <= 32; c = scan());
              boolean neg = c == '-';
              if (c == '-' || c == '+') {
                  c = scan();
              }
              for (; c >= '0' && c <= '9'; c = scan()) {
                  val = (val << 3) + (val << 1) + (c & 15);
              }
              return neg ? -val : val;
          }
      }
  	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 void printarray(int arr[])
          {
          	for (int i = 0; i < arr.length; i++)
  				System.out.print(arr[i]+" ");
          	System.out.println();
          }
      }
  }
  
  
  
  
  
  
  
  