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

#define int long long  

void solve() {
	int n;
	cin >> n;

	vector<int> c(n + 1);
	vector p(n + 1, vector<int>());
	for (int i = 1; i <= n; i++) {
		cin >> c[i];
		p[i].resize(c[i] + 1);
		for (int j = 1; j <= c[i]; j++) {
			cin >> p[i][j];
		}
	}

	vector<int> f(n + 1);
	for (int i = 1; i <= n; i++) {
		f[i] = i;
	}
	auto find = [&](int x) {
		while (x != f[x]) {
			x = f[x] = f[f[x]];
		}
		return x;
	};
	auto merge = [&](int x, int y) {
		x = find(x), y = find(y);
		if (x < y) {
			swap(x, y);
		}
		f[x] = y;
	};
	vector<int> fa(n + 1);
	for (int i = n; i >= 1; i--) {
		if (c[i] == 0) {
			continue;
		}
		for (int j = 1; j <= c[i]; j++) {
			fa[find(p[i][j])] = i;
			merge(p[i][j], i);
		}
	}

	for (int i = 2; i <= n; i++) {
		cout << i << " " << fa[i] << "\n";
	}
}

signed main() {  
    ios::sync_with_stdio(false);
    cin.tie(nullptr);  

    int t;
    cin >> t;
    while (t--) {
    	solve();
    }

    return 0;
}