#include <bits/stdc++.h>
using namespace std;
const double PI =
    3.141592653589793238462643383279502884197169399375105820974944;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int main() {
  int t, n, m, i, j, u, v, q1, q2;
  cin >> t;
  while (t--) {
    cin >> n;
    int left = 2, right = n;
    int ans = 0;
    v = 1;
    int sz1 = 1, sz2 = n - 1;
    cout << sz1 << ' ' << sz2 << ' ';
    cout << v << ' ';
    for (int i = (1); i <= (n); i++)
      if (i != v) cout << i << ' ';
    cout << '\n';
    cin >> q1;
    int mdist = q1;
    while (left <= right) {
      int mid = (left + right) / 2;
      sz1 = 1, sz2 = mid - left + 1;
      cout << sz1 << ' ' << mid - left + 1 << ' ';
      cout << 1 << ' ';
      for (int i = (left); i <= (mid); i++) cout << i << ' ';
      cout << '\n';
      cin >> q1;
      if (q1 == mdist) {
        v = mid;
        right = mid;
      } else
        left = mid + 1;
      if (left == right) {
        v = left;
        break;
      }
    }
    sz1 = 1, sz2 = n - 1;
    cout << sz1 << ' ' << sz2 << ' ';
    cout << v << ' ';
    for (int i = (1); i <= (n); i++)
      if (i != v) cout << i << ' ';
    cout << '\n';
    cin >> q1;
    if (q1 == -1) exit(0);
    ans = max(ans, q1);
    cout << "-1 " << ans << '\n';
  }
  return 0;
}
