#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;

#define int long long
#define pb push_back
#define all(s) s.begin(),s.end()
#define rall(s) s.rbegin(),s.rend()
#define pii pair<int,int>
#define fr first
#define sc second
#define bst ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define endl "\n"
#define no cout << "NO" << endl;
#define yes cout << "YES" << endl;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;

const int N = 5e5 + 10, mod = 1e9 + 7, inf = 1e18 + 7, logn = 23;
const double pi = acos(-1);

vector<vector<int>> gr;
int sz[N];
bool one = 1;
int scen;
int del, add;

void calc(int v, int pr = -1) {
	sz[v] = 1;
	for(auto it: gr[v]) {
		if(it != pr) {
			calc(it, v);
			sz[v] += sz[it];
		}
	}
	if(gr[v].size() == 1 && pr != -1) {
		del = v;
	}
}

int centroid(int v, int n, int pr = -1) {
	for(auto it: gr[v]) {
		if(it == pr) continue;

		if(sz[it] > n / 2) {
			return centroid(it, n, v);
		}
	}
	for(auto it: gr[v]) {
		if(it != pr) {
		  bool fine = (n - sz[it] <= n / 2);
			for(auto i: gr[it]) {
				if(i != v) {
					fine &= (sz[i] <= n / 2);
				}
			}
			if(fine) {
				scen = it;
				one = 0;
			}
		}
	}
	return v;
}

void getsc(int v, int pr) {
	for(auto it: gr[v]) {
		if(it != pr) {
			getsc(it, v);
		}
	}
	if(gr[v].size() == 1) {
		add = v;
	}
}

void solve() {
	//soln
	int n;
	cin >> n;
	gr = vector<vector<int>> (n + 1, vector<int> ());
	one = 1;
	for(int i = 1; i <= n; i++) {
		sz[i] = 0;
	}
	for(int i = 1; i < n; i++) {
		int l, r;
		cin >> l >> r;
		gr[l].pb(r);
		gr[r].pb(l);
	}

	calc(1);
	int cen = centroid(1, n);
	if(one) {
		cout << del << " " << gr[del][0] << endl;
		cout << del << " " << gr[del][0] << endl;
	} else {
		getsc(scen, cen);
		cout << del << " " << gr[del][0] << endl;
		cout << add << " " << del << endl;
	}
}

main() {
	bst;
	int t = 1;
	cin >> t;
	while(t--) {
		solve();
	}
}