#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    int min = 2, max = n;
    int x, y;
    int mid = (max + min) / 2;
    if (n == 2) {
      cout << 1 << " " << 1 << " " << 1 << " " << 2 << endl;
      cin >> x;
      cout << -1 << " " << x << endl;
      continue;
    }
    cout << 1 << " " << mid - min + 1 << " " << 1 << " ";
    for (int i = min; i <= mid; i++) {
      cout << i << " ";
    }
    cout << endl;
    cin >> x;
    cout << 1 << " " << max - mid << " " << 1 << " ";
    for (int i = mid + 1; i <= max; i++) {
      cout << i << " ";
    }
    cout << endl;
    cin >> y;
    if (y > x) {
      min = mid + 1;
    } else {
      y = x;
      max = mid;
    }
    while (min < max) {
      mid = (max + min) / 2;
      cout << 1 << " " << mid - min + 1 << " " << 1 << " ";
      for (int i = min; i <= mid; i++) {
        cout << i << " ";
      }
      cout << endl;
      cin >> x;
      if (x == y) {
        max = mid;
      } else {
        min = mid + 1;
      }
    }
    cout << 1 << " " << n - 1 << " " << min << " ";
    for (int i = 1; i <= n; i++) {
      if (i == min) continue;
      cout << i << " ";
    }
    cout << endl;
    cin >> x;
    cout << -1 << " " << x << endl;
  }
  return 0;
}
