#include<bits/stdc++.h>
#define INF 0x3f3f3f3f
#define mod 1e9+7;
#define endl '\n'
using namespace std;
typedef  long long LL;
typedef pair<int, int>PII;
inline LL gcd(LL a, LL b) { return b ? gcd(b, a % b) : a; }
inline LL lowbit(LL x) { return x & -x; }
const int N = 500010;
int n;
bool vis[N];
vector<int>v[N];
int t1, t2; //两个重心
int ans = INF;
int son[N];
void init() {
  for (int i = 1; i <= n; ++i) {
    v[i].clear();
    vis[i] = 0;
    son[i] = 0;
  }
  t1 = t2 = 0;
  ans = INF;
}
int dfs(int u) {
  vis[u] = true;
  int sum = 1, res = 0;
  for (int i = 0; i < v[u].size(); ++i) {
    int j = v[u][i];
    if (!vis[j]) {
      int s = dfs(j);
      sum += s;
      res = max(res, s);
    }
  }
  res = max(res, n - sum);
  if (ans >= res) {
    ans = res;
    son[u] = res;
    t2 = t1;
    t1 = u;
  }
  return sum;
}
void solve() {
  cin >> n;
  for (int i = 1; i <= n - 1; ++i) {
    int a, b; scanf("%d%d", &a, &b);
    v[a].push_back(b);
    v[b].push_back(a);
  }
  dfs(1); //找树的重心
  if (son[t1] != son[t2]) {
    printf("%d %d\n", t1, v[t1][0]);
    printf("%d %d\n", t1, v[t1][0]);
  }
  else {
    int u = 0;
    for (int i = 0; i < v[t1].size(); ++i) {
      int j = v[t1][i];
      if (j != t2) {
        u = j;
        break;
      }
    }
    printf("%d %d\n", t1, u);
    printf("%d %d\n", u, t2);
  }
  init();
}
int main() {
  int t; cin >> t;
  while(t--)
    solve();
  return 0;
}