#include <bits/stdc++.h>
using namespace std;
const long long int mod = 1e9 + 7;
long long int n;
long long int dfs(long long int v, vector<vector<long long int> >& adj,
                  vector<bool>& vis, vector<long long int>& sizes,
                  vector<long long int>& sub) {
  vis[v] = 1;
  long long int sum = 0;
  long long int maxi = 0;
  for (long long int u : adj[v]) {
    if (vis[u] == 0) {
      long long int x = dfs(u, adj, vis, sizes, sub);
      maxi = max(maxi, x);
      sum = sum + x;
    }
  }
  sum++;
  long long int left = n - sum;
  maxi = max(left, maxi);
  sizes[v] = maxi;
  sub[v] = sum;
  return sum;
}
int main() {
  long long int t;
  cin >> t;
  while (t--) {
    cin >> n;
    vector<vector<long long int> > adj(n);
    for (long long int i = 0; i < n - 1; i++) {
      long long int x, y;
      cin >> x >> y;
      x--, y--;
      adj[x].push_back(y);
      adj[y].push_back(x);
    }
    vector<long long int> sizes(n, 0);
    vector<bool> vis(n, 0);
    vector<long long int> sub(n, 0);
    long long int x = dfs(0, adj, vis, sizes, sub);
    long long int mini = *min_element(sizes.begin(), sizes.end());
    long long int count = 0;
    long long int ind;
    for (long long int i = 0; i < n; i++) {
      if (sizes[i] == mini) {
        count++;
        ind = i;
      }
    }
    if (count == 1) {
      cout << 1 << " " << adj[0][0] + 1 << endl;
      cout << 1 << " " << adj[0][0] + 1 << endl;
      continue;
    }
    vis.assign(n, 0);
    sizes.assign(n, 0);
    sub.assign(n, 0);
    x = dfs(ind, adj, vis, sizes, sub);
    long long int maxi = 0;
    for (long long int u : adj[ind]) {
      maxi = max(maxi, sub[u]);
    }
    for (long long int u : adj[ind]) {
      if (sub[u] == maxi) {
        if (adj[u][0] == ind) {
          cout << adj[u][1] + 1 << " " << u + 1 << endl;
          cout << ind + 1 << " " << adj[u][1] + 1 << endl;
        } else {
          cout << adj[u][0] + 1 << " " << u + 1 << endl;
          cout << ind + 1 << " " << adj[u][0] + 1 << endl;
        }
        break;
      }
    }
  }
}
