#include <bits/stdc++.h>
using namespace std;
long long int query(long long int l, long long int r) {
  cout << 1 << ' ' << (r - l + 1) << ' ' << 1 << ' ';
  for (; l <= r; ++l) cout << l << ' ';
  cout << '\n' << flush;
  cin >> r;
  return r;
}
void solve() {
  long long int n;
  cin >> n;
  long long int l = 2, r = n;
  long long int dist = query(2, n);
  while (l != r) {
    long long int m = (l + r) >> 1;
    if (query(l, m) == dist)
      r = m;
    else
      l = m + 1;
  }
  cout << 1 << ' ' << n - 1 << ' ';
  cout << l << ' ';
  for (long long int i = 1; i <= n; ++i)
    if (i != l) cout << i << ' ';
  cout << '\n' << flush;
  long long int res;
  cin >> res;
  cout << "-1 " << res << '\n' << flush;
}
int main() {
  ios::sync_with_stdio(0);
  long long int t;
  cin >> t;
  while (t--) {
    solve();
  }
  return 0;
}
