#include <bits/stdc++.h>
using namespace std;

int tong[1000010],a[2010],ji;
int t,n;
int main()
{
	scanf("%d",&t);
	while(t--)
	{
		scanf("%d",&n);
		n*=2;
		for(int i=1;i<=n;++i)
		scanf("%d",&a[i]);
		sort(a+1,a+n+1);
		int pd=0;
		for(int j=1;j<n;++j)
		{
			for(int i=1;i<=n;++i)
			tong[a[i]]=0;
			for(int i=1;i<=n;++i)
			tong[a[i]]++;
			tong[a[j]]--;
			int cur=a[n];
			tong[a[n]]--;
			for(int i=n-1;i>=1;--i)
			{
				if(tong[a[i]])
				{
//					cout<<a[i]<<" "<<cur<<endl;
					if(tong[cur-a[i]]&&a[i]!=cur-a[i])
					{
//						cout<<1<<endl;
						tong[a[i]]--;
						tong[cur-a[i]]--;
						cur=a[i];
					}
					else if(tong[cur-a[i]]>=2&&a[i]==cur-a[i])
					{
						tong[a[i]]-=2;
						cur=a[i];
					}
					else if(tong[cur-a[i]]==0)
					break;
				}			
			}
			int shu=0;
			ji=a[j];
			for(int i=1;i<=n;++i)
			{
				if(tong[a[i]])
				{
					shu+=tong[a[i]];
					break;
				}
			}
			if(shu==0)
			{
				printf("YES\n");
				printf("%d\n",a[n]+ji);
				printf("%d %d\n",a[n],ji);
				for(int i=1;i<=n;++i)
				tong[a[i]]=0;
				for(int i=1;i<=n;++i)
				tong[a[i]]++;
				tong[a[n]]--;
				tong[ji]--;
				ji=a[n];
				for(int i=n-1;i>=1;--i)
				{
					if(tong[a[i]])
					{
						printf("%d %d\n",a[i],ji-a[i]);
						tong[a[i]]--;
						tong[ji-a[i]]--;
						ji=a[i];
					}
				}
				pd=1;
				break;
			}
		}			
		if(pd==0)
		printf("NO\n");
		for(int i=1;i<=n;++i)
		tong[a[i]]=0;
	}
	return 0;
}