#include <bits/stdc++.h>
using namespace std;
const long long INF = (long long)1e18;
const int N = 2e5 + 5;
const long long MOD = 1e9 + 7;
int parent[N];
int gcd(int a, int b) {
  if (a == 0) return b;
  return gcd(b % a, a);
}
int lcm(int a, int b) { return (a * b) / gcd(a, b); }
long long pow(long long x, long long y, long long p) {
  if (y == 0) return 1;
  long long res = 1;
  x %= p;
  if (x == 0) return 0LL;
  while (y > 0) {
    if (y & 1) res = (res * x) % p;
    y >>= 1;
    x = (x * x) % p;
  }
  return res;
}
int find(int x) { return x == parent[x] ? x : parent[x] = find(parent[x]); }
void Union(int x, int y) {
  int xPar = find(x), yPar = find(y);
  if (xPar != yPar) parent[xPar] = yPar;
}
long long nCr(long long n, long long r) {
  long long res = 1;
  for (long long i = 1; i <= r; i++) {
    res = res * (n - r + i) / i;
  }
  return res;
}
int ask(int i, int j) {
  cout << "? " << i + 1 << ' ' << j + 1 << endl;
  int v;
  cin >> v;
  return v;
}
vector<int> Centroid(const vector<vector<int>> &g) {
  int n = g.size();
  vector<int> centroid;
  vector<int> sz(n);
  function<void(int, int)> dfs = [&](int u, int prev) {
    sz[u] = 1;
    bool is_centroid = true;
    for (auto v : g[u])
      if (v != prev) {
        dfs(v, u);
        sz[u] += sz[v];
        if (sz[v] > n / 2) is_centroid = false;
      }
    if (n - sz[u] > n / 2) is_centroid = false;
    if (is_centroid) centroid.push_back(u);
  };
  dfs(0, -1);
  return centroid;
}
void solve() {
  int n;
  cin >> n;
  vector<vector<int>> adj(n);
  for (int i = 1; i < n; i++) {
    int u, v;
    cin >> u >> v;
    u--, v--;
    adj[u].push_back(v);
    adj[v].push_back(u);
  }
  vector<int> centroids = Centroid(adj);
  if (centroids.size() == 1) {
    int c = centroids[0];
    cout << (c + 1) << ' ' << (adj[c][0] + 1) << endl;
    cout << (c + 1) << ' ' << (adj[c][0] + 1) << endl;
  } else {
    int c1 = centroids[0], c2 = centroids[1];
    int x;
    for (auto next : adj[c1]) {
      if (next != c2) {
        x = next;
        break;
      }
    }
    cout << (c1 + 1) << ' ' << (x + 1) << endl;
    cout << (c2 + 1) << ' ' << (x + 1) << endl;
  }
  return;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int t;
  cin >> t;
  while (t--) solve();
  return 0;
}
