#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 100;
inline long long read() {
  long long x = 0, f = 1;
  char ch = getchar();
  while (!isdigit(ch)) {
    if (ch == '-') f = -1;
    ch = getchar();
  }
  while (isdigit(ch)) {
    x = x * 10 + ch - 48;
    ch = getchar();
  }
  return x * f;
}
long long dp[maxn], siz[maxn];
vector<long long> g[maxn];
long long ans[10], tot = 0;
void dfs(long long u, long long fa, long long n) {
  siz[u] = 1;
  for (long long i = 0; i < g[u].size(); i++) {
    long long v = g[u][i];
    if (v == fa) continue;
    dfs(v, u, n);
    siz[u] += siz[v];
    dp[u] = max(dp[u], siz[v]);
  }
  if (max(dp[u], n - siz[u]) <= n / 2) ans[++tot] = u;
}
int main(void) {
  cin.tie(0);
  std::ios::sync_with_stdio(false);
  long long t;
  cin >> t;
  while (t--) {
    long long n;
    cin >> n;
    tot = 0;
    for (long long i = 0; i < n + 10; i++) g[i].clear(), dp[i] = 0, siz[i] = 0;
    for (long long i = 1; i < n; i++) {
      long long u, v;
      cin >> u >> v;
      g[u].push_back(v);
      g[v].push_back(u);
    }
    dfs(1, 0, n);
    if (1 == tot) {
      for (auto i : g[ans[tot]]) {
        cout << ans[tot] << " " << i << "\n";
        cout << ans[tot] << " " << i << "\n";
        break;
      }
    } else {
      for (long long i = 0; i < g[ans[1]].size(); i++) {
        long long v = g[ans[1]][i];
        if (v == ans[2]) continue;
        cout << ans[1] << " " << v << "\n";
        cout << ans[2] << " " << v << "\n";
        break;
      }
    }
  }
  return 0;
}
