#include <bits/stdc++.h>
using namespace std;
const double EPS = 1e-8;
const long long mod = (int)1e9 + 7;
int dx[] = {0, 0, -1, 1, 1, 1, -1, -1};
int dy[] = {1, -1, 0, 0, 1, -1, -1, 1};
const int N = 1000001;
void stop() {}
void file() {}
struct point {
  long long x, y;
};
unsigned long long gcd(unsigned long long a, unsigned long long b) {
  return !b ? a : gcd(b, a % b);
}
long long fixMod(long long a, long long b) { return ((a % b) + b) % b; }
double triangle_area(int x1, int y1, int x2, int y2, int x3, int y3) {
  return abs((x2 - x1) * (y3 - y1) - (y2 - y1) * (x3 - x1)) / 2.;
};
long long dis(pair<long long, long long> a, pair<long long, long long> b) {
  long long x = a.first - b.first, y = a.second - b.second;
  return abs(x) + abs(y);
}
unsigned long long LCM(unsigned long long a, unsigned long long b) {
  return a / gcd(a, b) * b;
}
long long power(long long x, long long y) {
  if (y == 0) return 1;
  if (y == 1) return x;
  long long r = power(x, y / 2);
  return r * r * power(x, y % 2);
}
bool isPrime(long long x) {
  if (x <= 1 || (x % 2 == 0 && x != 2)) return 0;
  for (long long i = 3; i * i <= x; i += 2) {
    if (x % i == 0) return 0;
  }
  return 1;
}
vector<vector<int>> v;
int n;
vector<int> dep;
int dfs(int node, int pr = -1) {
  int ret = 1;
  for (auto ch : v[node]) {
    if (ch != pr) {
      ret += dfs(ch, node);
    }
  }
  dep[node] = ret;
  return ret;
}
int aa = -1, bb = -1;
int x = -1;
void sol(int node, int pr = -1) {
  if (v[node].size() == 1 && aa == -1) {
    aa = node;
    bb = pr;
  }
  for (auto ch : v[node]) {
    if (ch != pr && ch != x) {
      sol(ch, node);
    }
  }
}
void solve() {
  cin >> n;
  v.clear();
  v.resize(n);
  dep.clear();
  map<pair<int, int>, bool> mp;
  int mx = 0;
  int st = 0;
  dep.resize(n);
  for (int i = 0; i < n - 1; i++) {
    int a, b;
    cin >> a >> b;
    a--;
    b--;
    mp[{a, b}] = true;
    v[a].push_back(b);
    v[b].push_back(a);
  }
  for (int i = 0; i < n; i++) {
    if (v[i].size() > mx) {
      mx = v[i].size();
      st = i;
    }
  }
  int ans = dfs(st);
  if (count(((dep).begin()), ((dep).end()), ans / 2) == 0 || ans & 1) {
    for (auto i : mp) {
      cout << i.first.first + 1 << " " << i.first.second + 1 << '\n';
      cout << i.first.first + 1 << " " << i.first.second + 1 << '\n';
      break;
    }
  } else {
    aa = -1;
    bb = -1;
    x = -1;
    for (int i = 0; i < n; i++) {
      if (dep[i] * 2 == ans) {
        x = i;
        break;
      }
    }
    sol(st);
    if (mp[{aa, bb}] == true) {
      cout << aa + 1 << " " << bb + 1 << '\n';
    } else {
      cout << bb + 1 << " " << aa + 1 << '\n';
    }
    if (v[aa].size() == 1) {
      cout << x + 1 << " " << aa + 1 << '\n';
    } else {
      cout << x + 1 << " " << bb + 1 << '\n';
    }
  }
  mp.clear();
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int t = 1;
  cin >> t;
  while (t--) {
    solve();
  }
  return 0;
}
