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.BufferedReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.io.PrintWriter;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.Comparator;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.LinkedHashMap;
  import java.util.LinkedList;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  import java.util.StringTokenizer;
  
  public class P1613B {
  	static PrintWriter out = new PrintWriter(System.out);
  	static MyFastReaderP1613B in = new MyFastReaderP1613B();
  	static long mod = (long) (1e9 + 7);
  
  	public static void main(String[] args) throws Exception {
  		int test = i();
  		while (test-- > 0) {
              int n=i();
              int[] arr=arrI(n);
              sort(arr);
              
              for(int i=1;i<=n/2;i++) out.println(arr[i]+" "+arr[0]);
              	
  			out.flush();
  		}
  		out.close();
  	}
  
  	static class pair {
  		long x, y;
  
  		pair(long ar, long ar2) {
  			x = ar;
  			y = ar2;
  		}
  	}
  
  	static void sort(long[] a) // check for long
  	{
  		ArrayList<Long> l = new ArrayList<>();
  		for (long i : a)
  			l.add(i);
  		Collections.sort(l);
  		for (int i = 0; i < a.length; i++)
  			a[i] = l.get(i);
  	}
  
  	static void sort(int[] a) {
  		ArrayList<Integer> l = new ArrayList<>();
  		for (int i : a)
  			l.add(i);
  		Collections.sort(l);
  		for (int i = 0; i < a.length; i++)
  			a[i] = l.get(i);
  	}
  
  	public static int gcd(int a, int b) {
  		if (a == 0)
  			return b;
  		return gcd(b % a, a);
  	}
  
  	static class DescendingComparator implements Comparator<Integer> {
  		public int compare(Integer a, Integer b) {
  			return b - a;
  		}
  	}
  
  	static class AscendingComparator implements Comparator<Integer> {
  		public int compare(Integer a, Integer b) {
  			return a - b;
  		}
  	}
  
  	static boolean isPalindrome(char X[]) {
  		int l = 0, r = X.length - 1;
  		while (l <= r) {
  			if (X[l] != X[r])
  				return false;
  			l++;
  			r--;
  		}
  		return true;
  	}
  
  	static long fact(long N) {
  		long num = 1L;
  		while (N >= 1) {
  			num = ((num % mod) * (N % mod)) % mod;
  			N--;
  		}
  		return num;
  	}
  
  	static long pow(long a, long b) {
  		long mod = 1000000007;
  		long pow = 1;
  		long x = a;
  		while (b != 0) {
  			if ((b & 1) != 0)
  				pow = (pow * x) % mod;
  			x = (x * x) % mod;
  			b /= 2;
  		}
  		return pow;
  	}
  
  	static long toggleBits(long x)// one's complement || Toggle bits
  	{
  		int n = (int) (Math.floor(Math.log(x) / Math.log(2))) + 1;
  
  		return ((1 << n) - 1) ^ x;
  	}
  
  	static int countBits(long a) {
  		return (int) (Math.log(a) / Math.log(2) + 1);
  	}
  
  	static boolean isPrime(long N) {
  		if (N <= 1)
  			return false;
  		if (N <= 3)
  			return true;
  		if (N % 2 == 0 || N % 3 == 0)
  			return false;
  		for (int i = 5; i * i <= N; i = i + 6)
  			if (N % i == 0 || N % (i + 2) == 0)
  				return false;
  		return true;
  	}
  
  	static long GCD(long a, long b) {
  		if (b == 0) {
  			return a;
  		} else
  			return GCD(b, a % b);
  	}
  
  	// Debugging Functions Starts
  
  	static void print(char A[]) {
  		for (char c : A)
  			System.out.print(c + " ");
  		System.out.println();
  	}
  
  	static void print(boolean A[]) {
  		for (boolean c : A)
  			System.out.print(c + " ");
  		System.out.println();
  	}
  
  	static void print(int A[]) {
  		for (int a : A)
  			System.out.print(a + " ");
  		System.out.println();
  	}
  
  	static void print(long A[]) {
  		for (long i : A)
  			System.out.print(i + " ");
  		System.out.println();
  
  	}
  
  	static void print(ArrayList<Integer> A) {
  		for (int a : A)
  			System.out.print(a + " ");
  		System.out.println();
  	}
  
  	// Debugging Functions END
  	// ----------------------
  	// IO FUNCTIONS STARTS
  	static HashMap<Integer, Integer> getHashMap(int A[]) {
  		HashMap<Integer, Integer> mp = new HashMap<>();
  		for (int a : A) {
  			int f = mp.getOrDefault(a, 0) + 1;
  			mp.put(a, f);
  		}
  		return mp;
  	}
  
  	public static Map<Character, Integer> mapSortByValue(Map<Character, Integer> hm) {
  		// Create a list from elements of HashMap
  		List<Map.Entry<Character, Integer>> list = new LinkedList<Map.Entry<Character, Integer>>(hm.entrySet());
  
  		// Sort the list
  		Collections.sort(list, new Comparator<Map.Entry<Character, Integer>>() {
  			public int compare(Map.Entry<Character, Integer> o1, Map.Entry<Character, Integer> o2) {
  				return o1.getValue() - o2.getValue();
  			}
  		});
  
  		// put data from sorted list to hashmap
  		Map<Character, Integer> temp = new LinkedHashMap<Character, Integer>();
  		for (Map.Entry<Character, Integer> aa : list) {
  			temp.put(aa.getKey(), aa.getValue());
  		}
  		return temp;
  	}
  	static String string() {
  		return in.nextLine();
  	}
  
  	static int i() {
  		return in.nextInt();
  	}
  
  	static long l() {
  		return in.nextLong();
  	}
  
  	static int[] arrI(int N) {
  		int A[] = new int[N];
  		for (int i = 0; i < N; i++) {
  			A[i] = in.nextInt();
  		}
  		return A;
  	}
  
  	static long[] arrL(int N) {
  		long A[] = new long[N];
  		for (int i = 0; i < A.length; i++)
  			A[i] = in.nextLong();
  		return A;
  	}
  
  }
  
  class MyFastReaderP1613B {
  	BufferedReader br;
  	StringTokenizer st;
  
  	public MyFastReaderP1613B() {
  		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());
  	}
  
  	String nextLine() {
  		String str = "";
  		try {
  			str = br.readLine();
  		} catch (IOException e) {
  			e.printStackTrace();
  		}
  		return str;
  	}
  }
  