#include <bits/stdc++.h>
using namespace std;
constexpr auto PI = 3.14159265358979323846L;
constexpr auto oo = numeric_limits<int>::max() / 2 - 2;
constexpr auto eps = 1e-6;
constexpr auto mod = 1000000007;
int query(int l, int m) {
  int r;
  cout << "1 " << m - l + 1 << " " << 1 << " ";
  for (int i = l; i < m + 1; i++) cout << i << " ";
  cout << '\n' << flush;
  cin >> r;
  return r;
}
int main() {
  ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
  int t, n;
  cin >> t;
  while (t--) {
    cin >> n;
    int q = n;
    int l = 2;
    int r = n;
    int max, max2;
    cout << "1 " << n - 1 << " ";
    for (int i = 1; i < n + 1; i++) cout << i << " ";
    cout << '\n' << flush;
    cin >> max;
    while (l < r) {
      int v;
      int m;
      m = (l + r) / 2;
      if (query(l, m) == max)
        r = m;
      else
        l = m + 1;
    }
    cout << "1 " << n - 1 << " ";
    cout << l << " ";
    for (int i = 1; i < n + 1; i++)
      if (i != l) cout << i << " ";
    cout << '\n' << flush;
    cin >> max2;
    cout << -1 << " " << max2 << '\n' << flush;
  }
}
