#include <bits/stdc++.h>
using namespace std;
long long qry(long long u, long long l, long long r) {
  cout << 1 << ' ' << r - l + 1 << ' ';
  cout << u << ' ';
  for (long long node = l; node <= r; node++) {
    if (node != u) {
      cout << node << ' ';
    }
  }
  cout << endl;
  long long input;
  cin >> input;
  return input;
}
void qry_(long long u, long long n) {
  cout << 1 << ' ' << n - 1 << ' ';
  cout << u << ' ';
  for (long long node = 1; node <= n; node++) {
    if (node != u) {
      cout << node << ' ';
    }
  }
  cout << endl;
  long long input;
  cin >> input;
  cout << -1 << ' ' << input << endl;
}
void solve() {
  long long n;
  cin >> n;
  long long poss = qry(1, 2, n);
  long long l = 2, r = n;
  long long node = l;
  while (l <= r) {
    long long mid = (l + r) >> 1;
    long long ans = qry(1, l, mid);
    if (ans == poss) {
      node = mid;
      r = mid - 1;
    } else {
      l = mid + 1;
    }
  }
  qry_(node, n);
}
signed main() {
  std ::ios_base ::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  long long t;
  cin >> t;
  while (t--) {
    solve();
  }
}
