#include <bits/stdc++.h>
using namespace std;
const long long mod = 1000000007;
const int maxn = 1e5 + 3;
void mf() { freopen("input.in", "r", stdin); }
int check(int l, int r) {
  cout << 1 << " " << (r - l + 1) << " " << 1;
  for (int i = l; i <= r; i++) cout << " " << i;
  cout << endl;
  fflush(stdout);
  int curr;
  cin >> curr;
  return curr;
}
int n;
void solve() {
  cin >> n;
  int mm = check(2, n);
  int l = 2, r = n;
  while (l < r) {
    int mid = (l + r) / 2;
    if (check(l, mid) == mm) {
      r = mid;
    } else {
      l = mid + 1;
    }
  }
  cout << 1 << " " << (n - 1) << " " << l;
  for (int i = 1; i <= n; i++) {
    if (i != l) cout << " " << i;
  }
  cout << endl;
  fflush(stdout);
  int ans;
  cin >> ans;
  cout << -1 << " " << ans << endl;
  fflush(stdout);
}
int main() {
  ios_base::sync_with_stdio(false);
  int ntest;
  cin >> ntest;
  while (ntest--) solve();
  return 0;
}
