#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
struct VectorHash {
  size_t operator()(const std::vector<int> &v) const {
    std::hash<int> hasher;
    size_t seed = 0;
    for (int i : v) {
      seed ^= hasher(i) + 0x9e3779b9 + (seed << 6) + (seed >> 2);
    }
    return seed;
  }
};
void __print(int x) { cerr << x; }
void __print(long x) { cerr << x; }
void __print(long long x) { cerr << x; }
void __print(unsigned x) { cerr << x; }
void __print(unsigned long x) { cerr << x; }
void __print(unsigned long long x) { cerr << x; }
void __print(float x) { cerr << x; }
void __print(double x) { cerr << x; }
void __print(long double x) { cerr << x; }
void __print(char x) { cerr << '\'' << x << '\''; }
void __print(const char *x) { cerr << '\"' << x << '\"'; }
void __print(const string &x) { cerr << '\"' << x << '\"'; }
void __print(bool x) { cerr << (x ? "true" : "false"); }
template <typename T, typename V>
void __print(const pair<T, V> &x) {
  cerr << '{';
  __print(x.first);
  cerr << ',';
  __print(x.second);
  cerr << '}';
}
template <typename T>
void __print(const T &x) {
  int f = 0;
  cerr << '{';
  for (auto &i : x) cerr << (f++ ? "," : ""), __print(i);
  cerr << "}";
}
void _print() { cerr << "]\n"; }
template <typename T, typename... V>
void _print(T t, V... v) {
  __print(t);
  if (sizeof...(v)) cerr << ", ";
  _print(v...);
}
long long int n, u, v, f, s, t;
vector<int> adj[100001];
vector<int> cent;
long long int sub[100001];
long long int dfs(int node, int p) {
  for (auto i : adj[node]) {
    if (i != p) sub[node] += dfs(i, node);
  }
  return sub[node];
}
void centroid(int node, int p) {
  bool f = 0;
  for (auto i : adj[node]) {
    if (i != p) {
      centroid(i, node);
      if (sub[i] > n / 2) f = 1;
    }
  }
  if (n - sub[node] > n / 2) f = 1;
  if (!f) cent.push_back(node);
  return;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long int times;
  cin >> times;
  while (times--) {
    cin >> n;
    for (int i = 0; i <= n; i++) {
      adj[i].clear();
      sub[i] = 1;
    }
    for (int i = 1; i < n; i++) {
      cin >> u >> v;
      adj[u].push_back(v);
      adj[v].push_back(u);
    }
    cent.clear();
    long long int k = dfs(1, -1);
    centroid(1, -1);
    if (cent.size() == 1) {
      cout << cent[0] << " " << adj[cent[0]][0] << '\n';
      cout << cent[0] << " " << adj[cent[0]][0] << '\n';
    } else if (cent.size()) {
      long long int s;
      for (auto i : adj[cent[0]]) {
        if (i != cent[1]) {
          s = i;
          break;
        }
      }
      cout << cent[0] << " " << s << '\n';
      cout << cent[1] << " " << s << '\n';
    }
  }
}
