#include <bits/stdc++.h>
using namespace std;
const int Z = 3 * (int)1e5 + 111;
const int INF = (int)1e9 + 111;
const int MODF = (int)1e9 + 7;
int ask(int v, int l, int r) {
  int x;
  cout << 1 << ' ' << r - l + 1 - (v >= l && v <= r ? 1 : 0) << ' ' << v << ' ';
  for (int i = l; i <= r; i++)
    if (i != v) cout << i << ' ';
  cout << endl;
  cin >> x;
  if (x == -1) exit(0);
  return x;
}
int big;
int find(int v, int l, int r) {
  while (r != l) {
    int mid = (l + r) / 2;
    int left_ans = ask(v, l, mid);
    if (left_ans == big)
      r = mid;
    else
      l = mid + 1;
  }
  return l;
}
int main() {
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    big = ask(1, 2, n);
    int ans = find(1, 2, n);
    cout << "-1 " << ask(ans, 1, n) << endl;
  }
  return 0;
}
